File: zsh.info, Node: Top, Next: The Z Shell Manual, Prev: (dir), Up: (dir)
The Z Shell Manual
******************
This Info file documents Zsh, a freely available UNIX command
interpreter (shell), which of the standard shells most closely
resembles the Korn shell (ksh), although it is not completely
compatible.
Version 4.3.10, last updated June 1, 2009.
* Menu:
* The Z Shell Manual::
* Introduction::
* Roadmap::
* Invocation::
* Files::
* Shell Grammar::
* Redirection::
* Command Execution::
* Functions::
* Jobs & Signals::
* Arithmetic Evaluation::
* Conditional Expressions::
* Prompt Expansion::
* Expansion::
* Parameters::
* Options::
* Shell Builtin Commands::
* Zsh Line Editor::
* Completion Widgets::
* Completion System::
* Completion Using compctl::
* Zsh Modules::
* Calendar Function System::
* TCP Function System::
* Zftp Function System::
* User Contributions::
--- Indices ---
* Concept Index::
* Variables Index::
* Options Index::
* Functions Index::
* Editor Functions Index::
* Style and Tag Index::
--- The Detailed Node Listing ---
Introduction
* Author::
* Availability::
* Mailing Lists::
* The Zsh FAQ::
* The Zsh Web Page::
* The Zsh Userguide::
* See Also::
Roadmap
Invocation
* Compatibility::
* Restricted Shell::
Shell Grammar
* Simple Commands & Pipelines::
* Precommand Modifiers::
* Complex Commands::
* Alternate Forms For Complex Commands::
* Reserved Words::
* Comments::
* Aliasing::
* Quoting::
Expansion
* History Expansion::
* Process Substitution::
* Parameter Expansion::
* Command Substitution::
* Arithmetic Expansion::
* Brace Expansion::
* Filename Expansion::
* Filename Generation::
Parameters
* Array Parameters::
* Positional Parameters::
* Local Parameters::
* Parameters Set By The Shell::
* Parameters Used By The Shell::
Options
* Specifying Options::
* Description of Options::
* Option Aliases::
* Single Letter Options::
Zsh Line Editor
* Movement::
* History Control::
* Modifying Text::
* Arguments::
* Completion::
* Miscellaneous::
Completion Widgets
* Completion Special Parameters::
* Completion Builtin Commands::
* Completion Condition Codes::
* Completion Matching Control::
* Completion Widget Example::
Completion System
* Initialization::
* Completion System Configuration::
* Control Functions::
* Bindable Commands::
* Completion Functions::
* Completion Directories::
Completion Using compctl
* Command Flags::
* Option Flags::
* Alternative Completion::
* Extended Completion::
* Example::
Zsh Modules
* The zsh/attr Module::
* The zsh/cap Module::
* The zsh/clone Module::
* The zsh/compctl Module::
* The zsh/complete Module::
* The zsh/complist Module::
* The zsh/computil Module::
* The zsh/curses Module::
* The zsh/datetime Module::
* The zsh/deltochar Module::
* The zsh/example Module::
* The zsh/files Module::
* The zsh/mapfile Module::
* The zsh/mathfunc Module::
* The zsh/newuser Module::
* The zsh/parameter Module::
* The zsh/pcre Module::
* The zsh/regex Module::
* The zsh/sched Module::
* The zsh/net/socket Module::
* The zsh/stat Module::
* The zsh/system Module::
* The zsh/net/tcp Module::
* The zsh/termcap Module::
* The zsh/terminfo Module::
* The zsh/zftp Module::
* The zsh/zle Module::
* The zsh/zleparameter Module::
* The zsh/zprof Module::
* The zsh/zpty Module::
* The zsh/zselect Module::
* The zsh/zutil Module::
TCP Function System
* TCP Functions::
* TCP Parameters::
* TCP Examples::
* TCP Bugs::
Zftp Function System
* Installation::
* Zftp Functions::
* Miscellaneous Features::
User Contributions
* Utilities::
* Prompt Themes::
* ZLE Functions::
* Other Functions::
File: zsh.info, Node: The Z Shell Manual, Next: Introduction, Prev: Top, Up: Top
1 The Z Shell Manual
********************
This document has been produced from the texinfo file zsh.texi,
included in the Doc sub-directory of the Zsh distribution.
1.1 Producing documentation from zsh.texi
=========================================
The texinfo source may be converted into several formats:
The Info manual
The Info format allows searching for topics, commands, functions,
etc. from the many Indices. The command `makeinfo zsh.texi' is
used to produce the Info documentation.
The printed manual
The command `texi2dvi zsh.texi' will output zsh.dvi which can then
be processed with `dvips' and optionally `gs' (Ghostscript) to
produce a nicely formatted printed manual.
The HTML manual
An HTML version of this manual is available at the Zsh web site
via:
http://zsh.sunsite.dk/Doc/.
(The HTML version is produced with `texi2html', which may be
obtained from http://www.nongnu.org/texi2html/. The command is
`texi2html -output . -ifinfo -split=chapter -node-files zsh.texi'.
If necessary, upgrade to version 1.78 of texi2html.)
For those who do not have the necessary tools to process texinfo,
precompiled documentation (PostScript, dvi, info and HTML formats) is
available from the zsh archive site or its mirrors, in the file
zsh-doc.tar.gz. (See *Note Availability:: for a list of sites.)
File: zsh.info, Node: Introduction, Next: Roadmap, Prev: The Z Shell Manual, Up: Top
2 Introduction
**************
Zsh is a UNIX command interpreter (shell) usable as an interactive
login shell and as a shell script command processor. Of the standard
shells, zsh most closely resembles `ksh' but includes many
enhancements. Zsh has command line editing, builtin spelling
correction, programmable command completion, shell functions (with
autoloading), a history mechanism, and a host of other features.
* Menu:
* Author::
* Availability::
* Mailing Lists::
* The Zsh FAQ::
* The Zsh Web Page::
* The Zsh Userguide::
* See Also::
File: zsh.info, Node: Author, Next: Availability, Up: Introduction
2.1 Author
==========
Zsh was originally written by Paul Falstad <pf AT zsh.org>. Zsh is now
maintained by the members of the zsh-workers mailing list
<zsh-workers AT sunsite.dk>. The development is currently coordinated by
Peter Stephenson <pws AT zsh.org>. The coordinator can be contacted at
<coordinator AT zsh.org>, but matters relating to the code should
generally go to the mailing list.
File: zsh.info, Node: Availability, Next: Mailing Lists, Prev: Author, Up: Introduction
2.2 Availability
================
Zsh is available from the following anonymous FTP sites. These mirror
sites are kept frequently up to date. The sites marked with _(H)_ may
be mirroring ftp.cs.elte.hu instead of the primary site.
Primary site
ftp://ftp.zsh.org/pub/zsh/
http://www.zsh.org/pub/zsh/
Australia
ftp://ftp.zsh.org/pub/zsh/
http://www.zsh.org/pub/zsh/
Denmark
ftp://sunsite.dk/pub/unix/shells/zsh/
Finland
ftp://ftp.funet.fi/pub/unix/shells/zsh/
Germany
ftp://ftp.fu-berlin.de/pub/unix/shells/zsh/ _(H)_
ftp://ftp.gmd.de/packages/zsh/
ftp://ftp.uni-trier.de/pub/unix/shell/zsh/
Hungary
ftp://ftp.cs.elte.hu/pub/zsh/
http://www.cs.elte.hu/pub/zsh/
ftp://ftp.kfki.hu/pub/packages/zsh/
Israel
ftp://ftp.math.technion.ac.il/pub/zsh/
http://www.math.technion.ac.il/pub/zsh/
Japan
ftp://ftp.win.ne.jp/pub/shell/zsh/
Korea
ftp://linux.sarang.net/mirror/system/shell/zsh/
Netherlands
ftp://ftp.demon.nl/pub/mirrors/zsh/
Norway
ftp://ftp.uit.no/pub/unix/shells/zsh/
Poland
ftp://sunsite.icm.edu.pl/pub/unix/shells/zsh/
Romania
ftp://ftp.roedu.net/pub/mirrors/ftp.zsh.org/pub/zsh/
ftp://ftp.kappa.ro/pub/mirrors/ftp.zsh.org/pub/zsh/
Slovenia
ftp://ftp.siol.net/mirrors/zsh/
Sweden
ftp://ftp.lysator.liu.se/pub/unix/zsh/
UK
ftp://ftp.net.lut.ac.uk/zsh/
ftp://sunsite.org.uk/packages/zsh/
USA
http://zsh.open-mirror.com/
The up-to-date source code is available via anonymous CVS from
Sourceforge. See http://sourceforge.net/projects/zsh/ for details.
File: zsh.info, Node: Mailing Lists, Next: The Zsh FAQ, Prev: Availability, Up: Introduction
2.3 Mailing Lists
=================
Zsh has 3 mailing lists:
<zsh-announce AT sunsite.dk>
Announcements about releases, major changes in the shell and the
monthly posting of the Zsh FAQ. (moderated)
<zsh-users AT sunsite.dk>
User discussions.
<zsh-workers AT sunsite.dk>
Hacking, development, bug reports and patches.
To subscribe or unsubscribe, send mail to the associated administrative
address for the mailing list.
<zsh-announce-subscribe AT sunsite.dk>
<zsh-users-subscribe AT sunsite.dk>
<zsh-workers-subscribe AT sunsite.dk>
<zsh-announce-unsubscribe AT sunsite.dk>
<zsh-users-unsubscribe AT sunsite.dk>
<zsh-workers-unsubscribe AT sunsite.dk>
YOU ONLY NEED TO JOIN ONE OF THE MAILING LISTS AS THEY ARE NESTED. All
submissions to `zsh-announce' are automatically forwarded to
`zsh-users'. All submissions to `zsh-users' are automatically
forwarded to `zsh-workers'.
If you have problems subscribing/unsubscribing to any of the mailing
lists, send mail to <listmaster AT zsh.org>. The mailing lists are
maintained by Karsten Thygesen <karthy AT kom.dk>.
The mailing lists are archived; the archives can be accessed via the
administrative addresses listed above. There is also a hypertext
archive, maintained by Geoff Wing <gcw AT zsh.org>, available at
http://www.zsh.org/mla/.
File: zsh.info, Node: The Zsh FAQ, Next: The Zsh Web Page, Prev: Mailing Lists, Up: Introduction
2.4 The Zsh FAQ
===============
Zsh has a list of Frequently Asked Questions (FAQ), maintained by Peter
Stephenson <pws AT zsh.org>. It is regularly posted to the newsgroup
`comp.unix.shell' and the `zsh-announce' mailing list. The latest
version can be found at any of the Zsh FTP sites, or at
http://www.zsh.org/FAQ/. The contact address for FAQ-related matters
is <faqmaster AT zsh.org>.
File: zsh.info, Node: The Zsh Web Page, Next: The Zsh Userguide, Prev: The Zsh FAQ, Up: Introduction
2.5 The Zsh Web Page
====================
Zsh has a web page which is located at http://www.zsh.org/. This is
maintained by Karsten Thygesen <karthy AT zsh.org>, of SunSITE Denmark.
The contact address for web-related matters is <webmaster AT zsh.org>.
File: zsh.info, Node: The Zsh Userguide, Next: See Also, Prev: The Zsh Web Page, Up: Introduction
2.6 The Zsh Userguide
=====================
A userguide is currently in preparation. It is intended to complement
the manual, with explanations and hints on issues where the manual can
be cabbalistic, hierographic, or downright mystifying (for example, the
word `hierographic' does not exist). It can be viewed in its current
state at http://zsh.sunsite.dk/Guide/. At the time of writing, chapters
dealing with startup files and their contents and the new completion
system were essentially complete.
2.7 The Zsh Wiki
================
A `wiki' website for zsh has been created at http://www.zshwiki.org/.
This is a site which can be added to and modified directly by users
without any special permission. You can add your own zsh tips and
configurations.
File: zsh.info, Node: See Also, Prev: The Zsh Userguide, Up: Introduction
2.8 See Also
============
man page sh(1), man page csh(1), man page tcsh(1), man page rc(1), man
page bash(1), man page ksh(1)
`IEEE Standard for information Technology - Portable Operating System
Interface (POSIX) - Part 2: Shell and Utilities', IEEE Inc, 1993, ISBN
1-55937-255-9.
File: zsh.info, Node: Roadmap, Next: Invocation, Prev: Introduction, Up: Top
3 Roadmap
*********
The Zsh Manual, like the shell itself, is large and often complicated.
This section of the manual provides some pointers to areas of the shell
that are likely to be of particular interest to new users, and indicates
where in the rest of the manual the documentation is to be found.
3.1 When the shell starts
=========================
When it starts, the shell reads commands from various files. These can
be created or edited to customize the shell. See *Note Files::.
If no personal initialization files exist for the current user, a
function is run to help you change some of the most common settings.
It won't appear if your administrator has disabled the zsh/newuser
module. The function is designed to be self-explanatory. You can run
it by hand with `autoload -Uz zsh-newuser-install; zsh-newuser-install
-f'. See also *Note User Configuration Functions::.
3.2 Interactive Use
===================
Interaction with the shell uses the builtin Zsh Line Editor, ZLE. This
is described in detail in *Note Zsh Line Editor::.
The first decision a user must make is whether to use the Emacs or Vi
editing mode as the keys for editing are substantially different. Emacs
editing mode is probably more natural for beginners and can be selected
explicitly with the command bindkey -e.
A history mechanism for retrieving previously typed lines (most simply
with the Up or Down arrow keys) is available; note that, unlike other
shells, zsh will not save these lines when the shell exits unless you
set appropriate variables, and the number of history lines retained by
default is quite small (30 lines). See the description of the shell
variables (referred to in the documentation as parameters) HISTFILE,
HISTSIZE and SAVEHIST in *Note Parameters Used By The Shell::.
The shell now supports the UTF-8 character set (and also others if
supported by the operating system). This is (mostly) handled
transparently by the shell, but the degree of support in terminal
emulators is variable. There is some discussion of this in the shell
FAQ, http://zsh.dotsrc.org/FAQ/ . Note in particular that for combining
characters to be handled the option COMBINING_CHARS needs to be set.
Because the shell is now more sensitive to the definition of the
character set, note that if you are upgrading from an older version of
the shell you should ensure that the appropriate variable, either LANG
(to affect all aspects of the shell's operation) or LC_CTYPE (to affect
only the handling of character sets) is set to an appropriate value.
This is true even if you are using a single-byte character set
including extensions of ASCII such as ISO-8859-1 or ISO-8859-15. See
the description of LC_CTYPE in *Note Parameters::.
3.2.1 Completion
----------------
Completion is a feature present in many shells. It allows the user to
type only a part (usually the prefix) of a word and have the shell fill
in the rest. The completion system in zsh is programmable. For
example, the shell can be set to complete email addresses in arguments
to the mail command from your ~/.abook/addressbook; usernames,
hostnames, and even remote paths in arguments to scp, and so on.
Anything that can be written in or glued together with zsh can be the
source of what the line editor offers as possible completions.
Zsh has two completion systems, an old, so called compctl completion
(named after the builtin command that serves as its complete and only
user interface), and a new one, referred to as compsys, organized as
library of builtin and user-defined functions. The two systems differ
in their interface for specifying the completion behavior. The new
system is more customizable and is supplied with completions for many
commonly used commands; it is therefore to be preferred.
The completion system must be enabled explicitly when the shell starts.
For more information see *Note Completion System::.
3.2.2 Extending the line editor
-------------------------------
Apart from completion, the line editor is highly extensible by means of
shell functions. Some useful functions are provided with the shell;
they provide facilities such as:
insert-composed-char
composing characters not found on the keyboard
match-words-by-style
configuring what the line editor considers a word when moving or
deleting by word
history-beginning-search-backward-end, etc.
alternative ways of searching the shell history
replace-string, replace-pattern
functions for replacing strings or patterns globally in the
command line
edit-command-line
edit the command line with an external editor.
See *Note ZLE Functions:: for descriptions of these.
3.3 Options
===========
The shell has a large number of options for changing its behaviour.
These cover all aspects of the shell; browsing the full documentation is
the only good way to become acquainted with the many possibilities. See
*Note Options::.
3.4 Pattern Matching
====================
The shell has a rich set of patterns which are available for file
matching (described in the documentation as `filename generation' and
also known for historical reasons as `globbing') and for use when
programming. These are described in *Note Filename Generation::.
Of particular interest are the following patterns that are not commonly
supported by other systems of pattern matching:
**
for matching over multiple directories
~, ^
the ability to exclude patterns from matching when the
EXTENDED_GLOB option is set
(...)
glob qualifiers, included in parentheses at the end of the pattern,
which select files by type (such as directories) or attribute
(such as size).
3.5 General Comments on Syntax
==============================
Although the syntax of zsh is in ways similar to the Korn shell, and
therefore more remotely to the original UNIX shell, the Bourne shell,
its default behaviour does not entirely correspond to those shells.
General shell syntax is introduced in *Note Shell Grammar::.
One commonly encountered difference is that variables substituted onto
the command line are not split into words. See the description of the
shell option SH_WORD_SPLIT in *Note Parameter Expansion::. In zsh, you
can either explicitly request the splitting (e.g. ${=foo}) or use an
array when you want a variable to expand to more than one word. See
*Note Array Parameters::.
3.6 Programming
===============
The most convenient way of adding enhancements to the shell is typically
by writing a shell function and arranging for it to be autoloaded.
Functions are described in *Note Functions::. Users changing from the
C shell and its relatives should notice that aliases are less used in
zsh as they don't perform argument substitution, only simple text
replacement.
A few general functions, other than those for the line editor described
above, are provided with the shell and are described in *Note User
Contributions::. Features include:
promptinit
a prompt theme system for changing prompts easily, see *Note
Prompt Themes::
zsh-mime-setup
a MIME-handling system which dispatches commands according to the
suffix of a file as done by graphical file managers
zcalc
a calculator
zargs
a version of xargs that makes the find command redundant
zmv
a command for renaming files by means of shell patterns.
File: zsh.info, Node: Invocation, Next: Files, Prev: Roadmap, Up: Top
4 Invocation
************
4.1 Invocation Options
======================
The following flags are interpreted by the shell when invoked to
determine where the shell will read commands from:
-c
Take the first argument as a command to execute, rather than
reading commands from a script or standard input. If any further
arguments are given, the first one is assigned to $0, rather than
being used as a positional parameter.
-i
Force shell to be interactive.
-s
Force shell to read commands from the standard input. If the -s
flag is not present and an argument is given, the first argument
is taken to be the pathname of a script to execute.
After the first one or two arguments have been appropriated as
described above, the remaining arguments are assigned to the positional
parameters.
For further options, which are common to invocation and the set
builtin, see *Note Options::.
Options may be specified by name using the -o option. -o acts like a
single-letter option, but takes a following string as the option name.
For example,
zsh -x -o shwordsplit scr
runs the script scr, setting the XTRACE option by the corresponding
letter `-x' and the SH_WORD_SPLIT option by name. Options may be
turned _off_ by name by using +o instead of -o. -o can be stacked up
with preceding single-letter options, so for example `-xo shwordsplit'
or `-xoshwordsplit' is equivalent to `-x -o shwordsplit'.
Options may also be specified by name in GNU long option style,
`--OPTION-NAME'. When this is done, `-' characters in the option name
are permitted: they are translated into `_', and thus ignored. So, for
example, `zsh --sh-word-split' invokes zsh with the SH_WORD_SPLIT
option turned on. Like other option syntaxes, options can be turned
off by replacing the initial `-' with a `+'; thus `+-sh-word-split' is
equivalent to `--no-sh-word-split'. Unlike other option syntaxes,
GNU-style long options cannot be stacked with any other options, so for
example `-x-shwordsplit' is an error, rather than being treated like
`-x --shwordsplit'.
The special GNU-style option `--version' is handled; it sends to
standard output the shell's version information, then exits
successfully. `--help' is also handled; it sends to standard output a
list of options that can be used when invoking the shell, then exits
successfully.
Option processing may be finished, allowing following arguments that
start with `-' or `+' to be treated as normal arguments, in two ways.
Firstly, a lone `-' (or `+') as an argument by itself ends option
processing. Secondly, a special option `--' (or `+-'), which may be
specified on its own (which is the standard POSIX usage) or may be
stacked with preceding options (so `-x-' is equivalent to `-x --').
Options are not permitted to be stacked after `--' (so `-x-f' is an
error), but note the GNU-style option form discussed above, where
`--shwordsplit' is permitted and does not end option processing.
Except when the `sh'/`ksh' emulation single-letter options are in
effect, the option `-b' (or `+b') ends option processing. `-b' is like
`--', except that further single-letter options can be stacked after
the `-b' and will take effect as normal.
* Menu:
* Compatibility::
* Restricted Shell::
File: zsh.info, Node: Compatibility, Next: Restricted Shell, Up: Invocation
4.2 Compatibility
=================
Zsh tries to emulate `sh' or `ksh' when it is invoked as sh or ksh
respectively; more precisely, it looks at the first letter of the name
by which it was invoked, excluding any initial `r' (assumed to stand
for `restricted'), and if that is `s' or `k' it will emulate `sh' or
`ksh'. Furthermore, if invoked as su (which happens on certain systems
when the shell is executed by the su command), the shell will try to
find an alternative name from the SHELL environment variable and
perform emulation based on that.
In `sh' and `ksh' compatibility modes the following parameters are not
special and not initialized by the shell: ARGC, argv, cdpath, fignore,
fpath, HISTCHARS, mailpath, MANPATH, manpath, path, prompt, PROMPT,
PROMPT2, PROMPT3, PROMPT4, psvar, status, watch.
The usual zsh startup/shutdown scripts are not executed. Login shells
source /etc/profile followed by $HOME/.profile. If the ENV environment
variable is set on invocation, $ENV is sourced after the profile
scripts. The value of ENV is subjected to parameter expansion, command
substitution, and arithmetic expansion before being interpreted as a
pathname. Note that the PRIVILEGED option also affects the execution
of startup files.
The following options are set if the shell is invoked as sh or ksh:
NO_BAD_PATTERN, NO_BANG_HIST, NO_BG_NICE, NO_EQUALS,
NO_FUNCTION_ARGZERO, GLOB_SUBST, NO_GLOBAL_EXPORT, NO_HUP,
INTERACTIVE_COMMENTS, KSH_ARRAYS, NO_MULTIOS, NO_NOMATCH, NO_NOTIFY,
POSIX_BUILTINS, NO_PROMPT_PERCENT, RM_STAR_SILENT, SH_FILE_EXPANSION,
SH_GLOB, SH_OPTION_LETTERS, SH_WORD_SPLIT. Additionally the BSD_ECHO
and IGNORE_BRACES options are set if zsh is invoked as sh. Also, the
KSH_OPTION_PRINT, LOCAL_OPTIONS, PROMPT_BANG, PROMPT_SUBST and
SINGLE_LINE_ZLE options are set if zsh is invoked as ksh.
File: zsh.info, Node: Restricted Shell, Prev: Compatibility, Up: Invocation
4.3 Restricted Shell
====================
When the basename of the command used to invoke zsh starts with the
letter `r' or the `-r' command line option is supplied at invocation,
the shell becomes restricted. Emulation mode is determined after
stripping the letter `r' from the invocation name. The following are
disabled in restricted mode:
* changing directories with the cd builtin
* changing or unsetting the PATH, path, MODULE_PATH, module_path,
SHELL, HISTFILE, HISTSIZE, GID, EGID, UID, EUID, USERNAME,
LD_LIBRARY_PATH, LD_AOUT_LIBRARY_PATH, LD_PRELOAD and
LD_AOUT_PRELOAD parameters
* specifying command names containing /
* specifying command pathnames using hash
* redirecting output to files
* using the exec builtin command to replace the shell with another
command
* using jobs -Z to overwrite the shell process' argument and
environment space
* using the ARGV0 parameter to override argv[0] for external commands
* turning off restricted mode with set +r or unsetopt RESTRICTED
These restrictions are enforced after processing the startup files. The
startup files should set up PATH to point to a directory of commands
which can be safely invoked in the restricted environment. They may
also add further restrictions by disabling selected builtins.
Restricted mode can also be activated any time by setting the
RESTRICTED option. This immediately enables all the restrictions
described above even if the shell still has not processed all startup
files.
File: zsh.info, Node: Files, Next: Shell Grammar, Prev: Invocation, Up: Top
5 Files
*******
5.1 Startup/Shutdown Files
==========================
Commands are first read from /etc/zshenv; this cannot be overridden.
Subsequent behaviour is modified by the RCS and GLOBAL_RCS options; the
former affects all startup files, while the second only affects global
startup files (those shown here with an path starting with a /). If
one of the options is unset at any point, any subsequent startup file(s)
of the corresponding type will not be read. It is also possible for a
file in $ZDOTDIR to re-enable GLOBAL_RCS. Both RCS and GLOBAL_RCS are
set by default.
Commands are then read from $ZDOTDIR/.zshenv. If the shell is a login
shell, commands are read from /etc/zprofile and then $ZDOTDIR/.zprofile. Then,
if the shell is interactive, commands are read from /etc/zshrc and then
$ZDOTDIR/.zshrc. Finally, if the shell is a login shell, /etc/zlogin
and $ZDOTDIR/.zlogin are read.
When a login shell exits, the files $ZDOTDIR/.zlogout and then
/etc/zlogout are read. This happens with either an explicit exit via
the exit or logout commands, or an implicit exit by reading end-of-file
from the terminal. However, if the shell terminates due to exec'ing
another process, the logout files are not read. These are also
affected by the RCS and GLOBAL_RCS options. Note also that the RCS
option affects the saving of history files, i.e. if RCS is unset when
the shell exits, no history file will be saved.
If ZDOTDIR is unset, HOME is used instead. Files listed above as being
in /etc may be in another directory, depending on the installation.
As /etc/zshenv is run for all instances of zsh, it is important that it
be kept as small as possible. In particular, it is a good idea to put
code that does not need to be run for every single shell behind a test
of the form `if [[ -o rcs ]]; then ...' so that it will not be executed
when zsh is invoked with the `-f' option.
5.2 Files
=========
$ZDOTDIR/.zshenv
$ZDOTDIR/.zprofile
$ZDOTDIR/.zshrc
$ZDOTDIR/.zlogin
$ZDOTDIR/.zlogout
${TMPPREFIX}* (default is /tmp/zsh*)
/etc/zshenv
/etc/zprofile
/etc/zshrc
/etc/zlogin
/etc/zlogout (installation-specific - /etc is the default)
Any of these files may be pre-compiled with the zcompile builtin
command (*Note Shell Builtin Commands::). If a compiled file exists
(named for the original file plus the .zwc extension) and it is newer
than the original file, the compiled file will be used instead.
File: zsh.info, Node: Shell Grammar, Next: Redirection, Prev: Files, Up: Top
6 Shell Grammar
***************
* Menu:
* Simple Commands & Pipelines::
* Precommand Modifiers::
* Complex Commands::
* Alternate Forms For Complex Commands::
* Reserved Words::
* Comments::
* Aliasing::
* Quoting::
File: zsh.info, Node: Simple Commands & Pipelines, Next: Precommand Modifiers, Up: Shell Grammar
6.1 Simple Commands & Pipelines
===============================
A _simple command_ is a sequence of optional parameter assignments
followed by blank-separated words, with optional redirections
interspersed. The first word is the command to be executed, and the
remaining words, if any, are arguments to the command. If a command
name is given, the parameter assignments modify the environment of the
command when it is executed. The value of a simple command is its exit
status, or 128 plus the signal number if terminated by a signal. For
example,
echo foo
is a simple command with arguments.
A _pipeline_ is either a simple command, or a sequence of two or more
simple commands where each command is separated from the next by `|' or
`|&'. Where commands are separated by `|', the standard output of the
first command is connected to the standard input of the next. `|&' is
shorthand for `2>&1 |', which connects both the standard output and the
standard error of the command to the standard input of the next. The
value of a pipeline is the value of the last command, unless the
pipeline is preceded by `!' in which case the value is the logical
inverse of the value of the last command. For example,
echo foo | sed 's/foo/bar/'
is a pipeline, where the output (`foo' plus a newline) of the first
command will be passed to the input of the second.
If a pipeline is preceded by `coproc', it is executed as a coprocess; a
two-way pipe is established between it and the parent shell. The shell
can read from or write to the coprocess by means of the `>&p' and `<&p'
redirection operators or with `print -p' and `read -p'. A pipeline
cannot be preceded by both `coproc' and `!'. If job control is active,
the coprocess can be treated in other than input and output as an
ordinary background job.
A _sublist_ is either a single pipeline, or a sequence of two or more
pipelines separated by `&&' or `||'. If two pipelines are separated by
`&&', the second pipeline is executed only if the first succeeds
(returns a zero status). If two pipelines are separated by `||', the
second is executed only if the first fails (returns a nonzero status).
Both operators have equal precedence and are left associative. The
value of the sublist is the value of the last pipeline executed. For
example,
dmesg | grep panic && print yes
is a sublist consisting of two pipelines, the second just a simple
command which will be executed if and only if the grep command returns
a zero status. If it does not, the value of the sublist is that return
status, else it is the status returned by the print (almost certainly
zero).
A _list_ is a sequence of zero or more sublists, in which each sublist
is terminated by `;', `&', `&|', `&!', or a newline. This terminator
may optionally be omitted from the last sublist in the list when the
list appears as a complex command inside `(...)' or `{...}'. When a
sublist is terminated by `;' or newline, the shell waits for it to
finish before executing the next sublist. If a sublist is terminated
by a `&', `&|', or `&!', the shell executes the last pipeline in it in
the background, and does not wait for it to finish (note the difference
from other shells which execute the whole sublist in the background).
A backgrounded pipeline returns a status of zero.
More generally, a list can be seen as a set of any shell commands
whatsoever, including the complex commands below; this is implied
wherever the word `list' appears in later descriptions. For example,
the commands in a shell function form a special sort of list.
File: zsh.info, Node: Precommand Modifiers, Next: Complex Commands, Prev: Simple Commands & Pipelines, Up: Shell Grammar
6.2 Precommand Modifiers
========================
A simple command may be preceded by a _precommand modifier_, which will
alter how the command is interpreted. These modifiers are shell
builtin commands with the exception of nocorrect which is a reserved
word.
-
The command is executed with a `-' prepended to its argv[0] string.
builtin
The command word is taken to be the name of a builtin command,
rather than a shell function or external command.
command [ -pvV ]
The command word is taken to be the name of an external command,
rather than a shell function or builtin. If the POSIX_BUILTINS
option is set, builtins will also be executed but certain special
properties of them are suppressed. The -p flag causes a default
path to be searched instead of that in $path. With the -v flag,
command is similar to whence and with -V, it is equivalent to
whence -v.
exec [ -cl ] [ -a ARGV0 ]
The following command together with any arguments is run in place
of the current process, rather than as a sub-process. The shell
does not fork and is replaced. The shell does not invoke
TRAPEXIT, nor does it source zlogout files. The options are
provided for compatibility with other shells.
The -c option clears the environment.
The -l option is equivalent to the - precommand modifier, to treat
the replacement command as a login shell; the command is executed
with a - prepended to its argv[0] string. This flag has no effect
if used together with the -a option.
The -a option is used to specify explicitly the argv[0] string
(the name of the command as seen by the process itself) to be used
by the replacement command and is directly equivalent to setting a
value for the ARGV0 environment variable.
nocorrect
Spelling correction is not done on any of the words. This must
appear before any other precommand modifier, as it is interpreted
immediately, before any parsing is done. It has no effect in
non-interactive shells.
noglob
Filename generation (globbing) is not performed on any of the
words.
File: zsh.info, Node: Complex Commands, Next: Alternate Forms For Complex Commands, Prev: Precommand Modifiers, Up: Shell Grammar
6.3 Complex Commands
====================
A _complex command_ in zsh is one of the following:
if LIST then LIST [ elif LIST then LIST ] ... [ else LIST ] fi
The if LIST is executed, and if it returns a zero exit status, the
then LIST is executed. Otherwise, the elif LIST is executed and
if its status is zero, the then LIST is executed. If each elif
LIST returns nonzero status, the else LIST is executed.
for NAME ... [ in WORD ... ] TERM do LIST done
where TERM is at least one newline or ;. Expand the list of
WORDs, and set the parameter NAME to each of them in turn,
executing LIST each time. If the in WORD is omitted, use the
positional parameters instead of the WORDs.
More than one parameter NAME can appear before the list of WORDs.
If N NAMEs are given, then on each execution of the loop the next
N WORDs are assigned to the corresponding parameters. If there
are more NAMEs than remaining WORDs, the remaining parameters are
each set to the empty string. Execution of the loop ends when
there is no remaining WORD to assign to the first NAME. It is
only possible for in to appear as the first NAME in the list, else
it will be treated as marking the end of the list.
for (( [EXPR1] ; [EXPR2] ; [EXPR3] )) do LIST done
The arithmetic expression EXPR1 is evaluated first (see *Note
Arithmetic Evaluation::). The arithmetic expression EXPR2 is
repeatedly evaluated until it evaluates to zero and when non-zero,
LIST is executed and the arithmetic expression EXPR3 evaluated.
If any expression is omitted, then it behaves as if it evaluated
to 1.
while LIST do LIST done
Execute the do LIST as long as the while LIST returns a zero exit
status.
until LIST do LIST done
Execute the do LIST as long as until LIST returns a nonzero exit
status.
repeat WORD do LIST done
WORD is expanded and treated as an arithmetic expression, which
must evaluate to a number N. LIST is then executed N times.
case WORD in [ [(] PATTERN [ | PATTERN ] ... ) LIST (;;|;&|;|) ] ... esac
Execute the LIST associated with the first PATTERN that matches
WORD, if any. The form of the patterns is the same as that used
for filename generation. See *Note Filename Generation::.
If the LIST that is executed is terminated with ;& rather than ;;,
the following list is also executed. The rule for the terminator
of the following list ;;, ;& or ;| is applied unless the esac is
reached.
If the LIST that is executed is terminated with ;| the shell
continues to scan the PATTERNs looking for the next match,
executing the corresponding LIST, and applying the rule for the
corresponding terminator ;;, ;& or ;|. Note that WORD is not
re-expanded; all applicable PATTERNs are tested with the same WORD.
select NAME [ in WORD ... TERM ] do LIST done
where TERM is one or more newline or ; to terminate the WORDs. Print
the set of WORDs, each preceded by a number. If the in WORD is
omitted, use the positional parameters. The PROMPT3 prompt is
printed and a line is read from the line editor if the shell is
interactive and that is active, or else standard input. If this
line consists of the number of one of the listed WORDs, then the
parameter NAME is set to the WORD corresponding to this number.
If this line is empty, the selection list is printed again.
Otherwise, the value of the parameter NAME is set to null. The
contents of the line read from standard input is saved in the
parameter REPLY. LIST is executed for each selection until a
break or end-of-file is encountered.
( LIST )
Execute LIST in a subshell. Traps set by the trap builtin are
reset to their default values while executing LIST.
{ LIST }
Execute LIST.
{ TRY-LIST } always { ALWAYS-LIST }
First execute TRY-LIST. Regardless of errors, or break, continue,
or return commands encountered within TRY-LIST, execute
ALWAYS-LIST. Execution then continues from the result of the
execution of TRY-LIST; in other words, any error, or break,
continue, or return command is treated in the normal way, as if
ALWAYS-LIST were not present. The two chunks of code are referred
to as the `try block' and the `always block'.
Optional newlines or semicolons may appear after the always; note,
however, that they may _not_ appear between the preceding closing
brace and the always.
An `error' in this context is a condition such as a syntax error
which causes the shell to abort execution of the current function,
script, or list. Syntax errors encountered while the shell is
parsing the code do not cause the ALWAYS-LIST to be executed. For
example, an erroneously constructed if block in try-list would
cause the shell to abort during parsing, so that always-list would
not be executed, while an erroneous substitution such as ${*foo*}
would cause a run-time error, after which always-list would be
executed.
An error condition can be tested and reset with the special integer
variable TRY_BLOCK_ERROR. Outside an always-list the value is
irrelevant, but it is initialised to -1. Inside always-list, the
value is 1 if an error occurred in the try-list, else 0. If
TRY_BLOCK_ERROR is set to 0 during the always-list, the error
condition caused by the try-list is reset, and shell execution
continues normally after the end of always-list. Altering the
value during the try-list is not useful (unless this forms part of
an enclosing always block).
Regardless of TRY_BLOCK_ERROR, after the end of always-list the
normal shell status $? is the value returned from always-list.
This will be non-zero if there was an error, even if
TRY_BLOCK_ERROR was set to zero.
The following executes the given code, ignoring any errors it
causes. This is an alternative to the usual convention of
protecting code by executing it in a subshell.
{
# code which may cause an error
} always {
# This code is executed regardless of the error.
(( TRY_BLOCK_ERROR = 0 ))
}
# The error condition has been reset.
An exit command (or a return command executed at the outermost
function level of a script) encountered in try-list does _not_
cause the execution of ALWAYS-LIST. Instead, the shell exits
immediately after any EXIT trap has been executed.
function WORD ... [ () ] [ TERM ] { LIST }
WORD ... () [ TERM ] { LIST }
WORD ... () [ TERM ] COMMAND
where TERM is one or more newline or ;. Define a function which
is referenced by any one of WORD. Normally, only one WORD is
provided; multiple WORDs are usually only useful for setting traps.
The body of the function is the LIST between the { and }. See
*Note Functions::.
If the option SH_GLOB is set for compatibility with other shells,
then whitespace may appear between between the left and right
parentheses when there is a single WORD; otherwise, the
parentheses will be treated as forming a globbing pattern in that
case.
time [ PIPELINE ]
The PIPELINE is executed, and timing statistics are reported on
the standard error in the form specified by the TIMEFMT parameter.
If PIPELINE is omitted, print statistics about the shell process
and its children.
[[ EXP ]]
Evaluates the conditional expression EXP and return a zero exit
status if it is true. See *Note Conditional Expressions:: for a
description of EXP.
File: zsh.info, Node: Alternate Forms For Complex Commands, Next: Reserved Words, Prev: Complex Commands, Up: Shell Grammar
6.4 Alternate Forms For Complex Commands
========================================
Many of zsh's complex commands have alternate forms. These particular
versions of complex commands should be considered deprecated and may be
removed in the future. The versions in the previous section should be
preferred instead.
The short versions below only work if SUBLIST is of the form `{ LIST }'
or if the SHORT_LOOPS option is set. For the if, while and until
commands, in both these cases the test part of the loop must also be
suitably delimited, such as by `[[ ... ]]' or `(( ... ))', else the end
of the test will not be recognized. For the for, repeat, case and
select commands no such special form for the arguments is necessary,
but the other condition (the special form of SUBLIST or use of the
SHORT_LOOPS option) still applies.
if LIST { LIST } [ elif LIST { LIST } ] ... [ else { LIST } ]
An alternate form of if. The rules mean that
if [[ -o ignorebraces ]] {
print yes
}
works, but
if true { # Does not work!
print yes
}
does _not_, since the test is not suitably delimited.
if LIST SUBLIST
A short form of the alternate `if'. The same limitations on the
form of LIST apply as for the previous form.
for NAME ... ( WORD ... ) SUBLIST
A short form of for.
for NAME ... [ in WORD ... ] TERM SUBLIST
where TERM is at least one newline or ;. Another short form of
for.
for (( [EXPR1] ; [EXPR2] ; [EXPR3] )) SUBLIST
A short form of the arithmetic for command.
foreach NAME ... ( WORD ... ) LIST end
Another form of for.
while LIST { LIST }
An alternative form of while. Note the limitations on the form of
LIST mentioned above.
until LIST { LIST }
An alternative form of until. Note the limitations on the form of
LIST mentioned above.
repeat WORD SUBLIST
This is a short form of repeat.
case WORD { [ [(] PATTERN [ | PATTERN ] ... ) LIST (;;|;&|;|) ] ... }
An alternative form of case.
select NAME [ in WORD TERM ] SUBLIST
where TERM is at least one newline or ;. A short form of select.
File: zsh.info, Node: Reserved Words, Next: Comments, Prev: Alternate Forms For Complex Commands, Up: Shell Grammar
6.5 Reserved Words
==================
The following words are recognized as reserved words when used as the
first word of a command unless quoted or disabled using disable -r:
do done esac then elif else fi for case if while function repeat time
until select coproc nocorrect foreach end ! [[ { }
Additionally, `}' is recognized in any position if the IGNORE_BRACES
option is not set.
File: zsh.info, Node: Comments, Next: Aliasing, Prev: Reserved Words, Up: Shell Grammar
6.6 Comments
============
In non-interactive shells, or in interactive shells with the
INTERACTIVE_COMMENTS option set, a word beginning with the third
character of the histchars parameter (`#' by default) causes that word
and all the following characters up to a newline to be ignored.
File: zsh.info, Node: Aliasing, Next: Quoting, Prev: Comments, Up: Shell Grammar
6.7 Aliasing
============
Every token in the shell input is checked to see if there is an alias
defined for it. If so, it is replaced by the text of the alias if it
is in command position (if it could be the first word of a simple
command), or if the alias is global. If the text ends with a space,
the next word in the shell input is treated as though it were in
command position for purposes of alias expansion. An alias is defined
using the alias builtin; global aliases may be defined using the -g
option to that builtin.
Alias expansion is done on the shell input before any other expansion
except history expansion. Therefore, if an alias is defined for the
word foo, alias expansion may be avoided by quoting part of the word,
e.g. \foo. But there is nothing to prevent an alias being defined for
\foo as well.
There is a commonly encountered problem with aliases illustrated by the
following code:
alias echobar='echo bar'; echobar
This prints a message that the command echobar could not be found.
This happens because aliases are expanded when the code is read in; the
entire line is read in one go, so that when echobar is executed it is
too late to expand the newly defined alias. This is often a problem in
shell scripts, functions, and code executed with `source' or `.'.
Consequently, use of functions rather than aliases is recommended in
non-interactive code.
File: zsh.info, Node: Quoting, Prev: Aliasing, Up: Shell Grammar
6.8 Quoting
===========
A character may be QUOTED (that is, made to stand for itself) by
preceding it with a `\'. `\' followed by a newline is ignored.
A string enclosed between `$'' and `'' is processed the same way as the
string arguments of the print builtin, and the resulting string is
considered to be entirely quoted. A literal `'' character can be
included in the string by using the `\'' escape.
All characters enclosed between a pair of single quotes ('') that is
not preceded by a `$' are quoted. A single quote cannot appear within
single quotes unless the option RC_QUOTES is set, in which case a pair
of single quotes are turned into a single quote. For example,
print ''''
outputs nothing apart from a newline if RC_QUOTES is not set, but one
single quote if it is set.
Inside double quotes (""), parameter and command substitution occur,
and `\' quotes the characters `\', ``', `"', and `$'.
File: zsh.info, Node: Redirection, Next: Command Execution, Prev: Shell Grammar, Up: Top
7 Redirection
*************
If a command is followed by & and job control is not active, then the
default standard input for the command is the empty file /dev/null.
Otherwise, the environment for the execution of a command contains the
file descriptors of the invoking shell as modified by input/output
specifications.
The following may appear anywhere in a simple command or may precede or
follow a complex command. Expansion occurs before WORD or DIGIT is
used except as noted below. If the result of substitution on WORD
produces more than one filename, redirection occurs for each separate
filename in turn.
< WORD
Open file WORD for reading as standard input.
<> WORD
Open file WORD for reading and writing as standard input. If the
file does not exist then it is created.
> WORD
Open file WORD for writing as standard output. If the file does
not exist then it is created. If the file exists, and the CLOBBER
option is unset, this causes an error; otherwise, it is truncated
to zero length.
>| WORD
>! WORD
Same as >, except that the file is truncated to zero length if it
exists, even if CLOBBER is unset.
>> WORD
Open file WORD for writing in append mode as standard output. If
the file does not exist, and the CLOBBER option is unset, this
causes an error; otherwise, the file is created.
>>| WORD
>>! WORD
Same as >>, except that the file is created if it does not exist,
even if CLOBBER is unset.
<<[-] WORD
The shell input is read up to a line that is the same as WORD, or
to an end-of-file. No parameter expansion, command substitution or
filename generation is performed on WORD. The resulting document,
called a _here-document_, becomes the standard input.
If any character of WORD is quoted with single or double quotes or
a `\', no interpretation is placed upon the characters of the
document. Otherwise, parameter and command substitution occurs,
`\' followed by a newline is removed, and `\' must be used to
quote the characters `\', `$', ``' and the first character of WORD.
Note that WORD itself does not undergo shell expansion. Backquotes
in WORD do not have their usual effect; instead they behave
similarly to double quotes, except that the backquotes themselves
are passed through unchanged. (This information is given for
completeness and it is not recommended that backquotes be used.)
Quotes in the form $'...' have their standard effect of expanding
backslashed references to special characters.
If <<- is used, then all leading tabs are stripped from WORD and
from the document.
<<< WORD
Perform shell expansion on WORD and pass the result to standard
input. This is known as a _here-string_. Compare the use of WORD
in here-documents above, where WORD does not undergo shell
expansion.
<& NUMBER
>& NUMBER
The standard input/output is duplicated from file descriptor
NUMBER (see man page dup2(2)).
<& -
>& -
Close the standard input/output.
<& p
>& p
The input/output from/to the coprocess is moved to the standard
input/output.
>& WORD
&> WORD
(Except where `>& WORD' matches one of the above syntaxes; `&>'
can always be used to avoid this ambiguity.) Redirects both
standard output and standard error (file descriptor 2) in the
manner of `> WORD'. Note that this does _not_ have the same
effect as `> WORD 2>&1' in the presence of multios (see the
section below).
>&| WORD
>&! WORD
&>| WORD
&>! WORD
Redirects both standard output and standard error (file descriptor
2) in the manner of `>| WORD'.
>>& WORD
&>> WORD
Redirects both standard output and standard error (file descriptor
2) in the manner of `>> WORD'.
>>&| WORD
>>&! WORD
&>>| WORD
&>>! WORD
Redirects both standard output and standard error (file descriptor
2) in the manner of `>>| WORD'.
If one of the above is preceded by a digit, then the file descriptor
referred to is that specified by the digit instead of the default 0 or
1. The order in which redirections are specified is significant. The
shell evaluates each redirection in terms of the (_file descriptor_,
_file_) association at the time of evaluation. For example:
... 1>FNAME 2>&1
first associates file descriptor 1 with file FNAME. It then associates
file descriptor 2 with the file associated with file descriptor 1 (that
is, FNAME). If the order of redirections were reversed, file
descriptor 2 would be associated with the terminal (assuming file
descriptor 1 had been) and then file descriptor 1 would be associated
with file FNAME.
If instead of a digit one of the operators above is preceded by a valid
identifier enclosed in braces, the shell will open a new file
descriptor that is guaranteed to be at least 10 and set the parameter
named by the identifier to the file descriptor opened. No whitespace
is allowed between the closing brace and the redirection character.
The option IGNORE_BRACES must not be set. For example:
... {myfd}>&1
This opens a new file descriptor that is a duplicate of file descriptor
1 and sets the parameter myfd to the number of the file descriptor,
which will be at least 10. The new file descriptor can be written to
using the syntax >&$myfd.
The syntax {VARID}>&-, for example {myfd}>&-, may be used to close a
file descriptor opened in this fashion. Note that the parameter given
by VARID must previously be set to a file descriptor in this case.
It is an error to open or close a file descriptor in this fashion when
the parameter is readonly. However, it is not an error to read or
write a file descriptor using <&$PARAM or >&$PARAM if PARAM is readonly.
If the option CLOBBER is unset, it is an error to open a file
descriptor using a parameter that is already set to an open file
descriptor previously allocated by this mechanism. Unsetting the
parameter before using it for allocating a file descriptor avoids the
error.
Note that this mechanism merely allocates or closes a file descriptor;
it does not perform any redirections from or to it. It is usually
convenient to allocate a file descriptor prior to use as an argument to
exec. The following shows a typical sequence of allocation, use, and
closing of a file descriptor:
integer myfd
exec {myfd}>~/logs/mylogfile.txt
print This is a log message. >&$myfd
exec {myfd}>&-
Note that the expansion of the variable in the expression >&$myfd
occurs at the point the redirection is opened. This is after the
expansion of command arguments and after any redirections to the left
on the command line have been processed.
The `|&' command separator described in *Note Simple Commands &
Pipelines:: is a shorthand for `2>&1 |'.
The various forms of process substitution, `<(LIST)', and `=(LIST())'
for input and `>(LIST)' for output, are often used together with
redirection. For example, if WORD in an output redirection is of the
form `>(LIST)' then the output is piped to the command represented by
LIST. See *Note Process Substitution::.
7.1 Multios
===========
If the user tries to open a file descriptor for writing more than once,
the shell opens the file descriptor as a pipe to a process that copies
its input to all the specified outputs, similar to `tee', provided the
MULTIOS option is set, as it is by default. Thus:
date >foo >bar
writes the date to two files, named `foo' and `bar'. Note that a pipe
is an implicit redirection; thus
date >foo | cat
writes the date to the file `foo', and also pipes it to cat.
If the MULTIOS option is set, the word after a redirection operator is
also subjected to filename generation (globbing). Thus
: > *
will truncate all files in the current directory, assuming there's at
least one. (Without the MULTIOS option, it would create an empty file
called `*'.) Similarly, you can do
echo exit 0 >> *.sh
If the user tries to open a file descriptor for reading more than once,
the shell opens the file descriptor as a pipe to a process that copies
all the specified inputs to its output in the order specified, similar
to `cat', provided the MULTIOS option is set. Thus
sort <foo <fubar
or even
sort <f{oo,ubar}
is equivalent to `cat foo fubar | sort'.
Expansion of the redirection argument occurs at the point the
redirection is opened, at the point described above for the expansion
of the variable in >&$myfd.
Note that a pipe is an implicit redirection; thus
cat bar | sort <foo
is equivalent to `cat bar foo | sort' (note the order of the inputs).
If the MULTIOS option is _un_set, each redirection replaces the
previous redirection for that file descriptor. However, all files
redirected to are actually opened, so
echo foo > bar > baz
when MULTIOS is unset will truncate bar, and write `foo' into baz.
There is a problem when an output multio is attached to an external
program. A simple example shows this:
cat file >file1 >file2
cat file1 file2
Here, it is possible that the second `cat' will not display the full
contents of file1 and file2 (i.e. the original contents of file
repeated twice).
The reason for this is that the multios are spawned after the cat
process is forked from the parent shell, so the parent shell does not
wait for the multios to finish writing data. This means the command as
shown can exit before file1 and file2 are completely written. As a
workaround, it is possible to run the cat process as part of a job in
the current shell:
{ cat file } >file >file2
Here, the {...} job will pause to wait for both files to be written.
7.2 Redirections with no command
================================
When a simple command consists of one or more redirection operators and
zero or more parameter assignments, but no command name, zsh can behave
in several ways.
If the parameter NULLCMD is not set or the option CSH_NULLCMD is set,
an error is caused. This is the `csh' behavior and CSH_NULLCMD is set
by default when emulating `csh'.
If the option SH_NULLCMD is set, the builtin `:' is inserted as a
command with the given redirections. This is the default when emulating
`sh' or `ksh'.
Otherwise, if the parameter NULLCMD is set, its value will be used as a
command with the given redirections. If both NULLCMD and READNULLCMD
are set, then the value of the latter will be used instead of that of
the former when the redirection is an input. The default for NULLCMD
is `cat' and for READNULLCMD is `more'. Thus
< file
shows the contents of file on standard output, with paging if that is a
terminal. NULLCMD and READNULLCMD may refer to shell functions.
File: zsh.info, Node: Command Execution, Next: Functions, Prev: Redirection, Up: Top
8 Command Execution
*******************
If a command name contains no slashes, the shell attempts to locate it.
If there exists a shell function by that name, the function is invoked
as described in *Note Functions::. If there exists a shell builtin by
that name, the builtin is invoked.
Otherwise, the shell searches each element of $path for a directory
containing an executable file by that name. If the search is
unsuccessful, the shell prints an error message and returns a nonzero
exit status.
If execution fails because the file is not in executable format, and
the file is not a directory, it is assumed to be a shell script.
/bin/sh is spawned to execute it. If the program is a file beginning
with `#!', the remainder of the first line specifies an interpreter for
the program. The shell will execute the specified interpreter on
operating systems that do not handle this executable format in the
kernel.
If no external command is found but a function command_not_found_handler
exists the shell executes this function with all command line
arguments. The function should return status zero if it successfully
handled the command, or non-zero status if it failed. In the latter
case the standard handling is applied: `command not found' is printed
to standard error and the shell exits with status 127. Note that the
handler is executed in a subshell forked to execute an external
command, hence changes to directories, shell parameters, etc. have no
effect on the main shell.
File: zsh.info, Node: Functions, Next: Jobs & Signals, Prev: Command Execution, Up: Top
9 Functions
***********
Shell functions are defined with the function reserved word or the
special syntax `FUNCNAME ()'. Shell functions are read in and stored
internally. Alias names are resolved when the function is read.
Functions are executed like commands with the arguments passed as
positional parameters. (See *Note Command Execution::.)
Functions execute in the same process as the caller and share all files
and present working directory with the caller. A trap on EXIT set
inside a function is executed after the function completes in the
environment of the caller.
The return builtin is used to return from function calls.
Function identifiers can be listed with the functions builtin. Functions
can be undefined with the unfunction builtin.
9.1 Autoloading Functions
=========================
A function can be marked as _undefined_ using the autoload builtin (or
`functions -u' or `typeset -fu'). Such a function has no body. When
the function is first executed, the shell searches for its definition
using the elements of the fpath variable. Thus to define functions for
autoloading, a typical sequence is:
fpath=(~/myfuncs $fpath)
autoload myfunc1 myfunc2 ...
The usual alias expansion during reading will be suppressed if the
autoload builtin or its equivalent is given the option -U. This is
recommended for the use of functions supplied with the zsh distribution. Note
that for functions precompiled with the zcompile builtin command the
flag -U must be provided when the .zwc file is created, as the
corresponding information is compiled into the latter.
For each ELEMENT in fpath, the shell looks for three possible files,
the newest of which is used to load the definition for the function:
ELEMENT.zwc
A file created with the zcompile builtin command, which is
expected to contain the definitions for all functions in the
directory named ELEMENT. The file is treated in the same manner
as a directory containing files for functions and is searched for
the definition of the function. If the definition is not found,
the search for a definition proceeds with the other two
possibilities described below.
If ELEMENT already includes a .zwc extension (i.e. the extension
was explicitly given by the user), ELEMENT is searched for the
definition of the function without comparing its age to that of
other files; in fact, there does not need to be any directory
named ELEMENT without the suffix. Thus including an element such
as `/usr/local/funcs.zwc' in fpath will speed up the search for
functions, with the disadvantage that functions included must be
explicitly recompiled by hand before the shell notices any changes.
ELEMENT/FUNCTION.zwc
A file created with zcompile, which is expected to contain the
definition for FUNCTION. It may include other function definitions
as well, but those are neither loaded nor executed; a file found
in this way is searched _only_ for the definition of FUNCTION.
ELEMENT/FUNCTION
A file of zsh command text, taken to be the definition for
FUNCTION.
In summary, the order of searching is, first, in the _parents of_
directories in fpath for the newer of either a compiled directory or a
directory in fpath; second, if more than one of these contains a
definition for the function that is sought, the leftmost in the fpath
is chosen; and third, within a directory, the newer of either a compiled
function or an ordinary function definition is used.
If the KSH_AUTOLOAD option is set, or the file contains only a simple
definition of the function, the file's contents will be executed. This
will normally define the function in question, but may also perform
initialization, which is executed in the context of the function
execution, and may therefore define local parameters. It is an error
if the function is not defined by loading the file.
Otherwise, the function body (with no surrounding `FUNCNAME() {...}')
is taken to be the complete contents of the file. This form allows the
file to be used directly as an executable shell script. If processing
of the file results in the function being re-defined, the function
itself is not re-executed. To force the shell to perform
initialization and then call the function defined, the file should
contain initialization code (which will be executed then discarded) in
addition to a complete function definition (which will be retained for
subsequent calls to the function), and a call to the shell function,
including any arguments, at the end.
For example, suppose the autoload file func contains
func() { print This is func; }
print func is initialized
then `func; func' with KSH_AUTOLOAD set will produce both messages on
the first call, but only the message `This is func' on the second and
subsequent calls. Without KSH_AUTOLOAD set, it will produce the
initialization message on the first call, and the other message on the
second and subsequent calls.
It is also possible to create a function that is not marked as
autoloaded, but which loads its own definition by searching fpath, by
using `autoload -X' within a shell function. For example, the
following are equivalent:
myfunc() {
autoload -X
}
myfunc args...
and
unfunction myfunc # if myfunc was defined
autoload myfunc
myfunc args...
In fact, the functions command outputs `builtin autoload -X' as the
body of an autoloaded function. This is done so that
eval "$(functions)"
produces a reasonable result. A true autoloaded function can be
identified by the presence of the comment `# undefined' in the body,
because all comments are discarded from defined functions.
To load the definition of an autoloaded function myfunc without
executing myfunc, use:
autoload +X myfunc
9.2 Anonymous Functions
=======================
If no name is given for a function, it is `anonymous' and is handled
specially. Either form of function definition may be used: a `()' with
no preceding name, or a `function' with an immediately following open
brace. The function is executed immediately at the point of definition
and is not stored for future use. The function name is set to `(anon)'
and the parameter list passed to the function is empty. Note that this
means the argument list of any enclosing script or function is hidden.
Redirections may be applied to the anonymous function in the same
manner as to a current-shell structure enclosed in braces. The main
use of anonymous functions is to provide a scope for local variables.
This is particularly convenient in start-up files as these do not
provide their own local variable scope.
For example,
variable=outside
function {
local variable=inside
print "I am $variable"
}
print "I am $variable"
outputs the following:
I am inside
I am outside
Note that function definitions with arguments that expand to nothing,
for example `name=; function $name { ... }', are not treated as
anonymous functions. Instead, they are treated as normal function
definitions where the definition is silently discarded.
9.3 Special Functions
=====================
Certain functions, if defined, have special meaning to the shell.
9.3.1 Hook Functions
--------------------
For the functions below, it is possible to define an array that has the
same name as the function with `_functions' appended. Any element in
such an array is taken as the name of a function to execute; it is
executed in the same context and with the same arguments as the basic
function. For example, if $chpwd_functions is an array containing the
values `mychpwd', `chpwd_save_dirstack', then the shell attempts to
execute the functions `chpwd', `mychpwd' and `chpwd_save_dirstack', in
that order. Any function that does not exist is silently ignored. A
function found by this mechanism is referred to elsewhere as a `hook
function'. An error in any function causes subsequent functions not to
be run. Note further that an error in a precmd hook causes an
immediately following periodic function not to run (though it may run
at the next opportunity).
chpwd
Executed whenever the current working directory is changed.
periodic
If the parameter PERIOD is set, this function is executed every
$PERIOD seconds, just before a prompt. Note that if multiple
functions are defined using the array periodic_functions only one
period is applied to the complete set of functions, and the
scheduled time is not reset if the list of functions is altered.
Hence the set of functions is always called together.
precmd
Executed before each prompt. Note that precommand functions are
not re-executed simply because the command line is redrawn, as
happens, for example, when a notification about an exiting job is
displayed.
preexec
Executed just after a command has been read and is about to be
executed. If the history mechanism is active (and the line was not
discarded from the history buffer), the string that the user typed
is passed as the first argument, otherwise it is an empty string.
The actual command that will be executed (including expanded
aliases) is passed in two different forms: the second argument is
a single-line, size-limited version of the command (with things
like function bodies elided); the third argument contains the full
text that is being executed.
zshaddhistory
Executed when a history line has been read interactively, but
before it is executed. The sole argument is the complete history
line (so that any terminating newline will still be present).
If any of the hook functions return a non-zero value the history
line will not be saved, although it lingers in the history until
the next line is executed allow you to reuse or edit it
immediately.
A hook function may call `fc -p ...' to switch the history context
so that the history is saved in a different file from the that in
the global HISTFILE parameter. This is handled specially: the
history context is automatically restored after the processing of
the history line is finished.
The following example function first adds the history line to the
normal history with the newline stripped, which is usually the
correct behaviour. Then it switches the history context so that
the line will be written to a history file in the current
directory.
zshaddhistory() {
print -sr -- ${1%%$'\n'}
fc -p .zsh_local_history
}
zshexit
Executed at the point where the main shell is about to exit
normally. This is not called by exiting subshells, nor when the
exec precommand modifier is used before an external command.
Also, unlike TRAPEXIT, it is not called when functions exit.
9.3.2 Trap Functions
--------------------
The functions below are treated specially but do not have corresponding
hook arrays.
TRAPNAL
If defined and non-null, this function will be executed whenever
the shell catches a signal SIGNAL, where NAL is a signal name as
specified for the kill builtin. The signal number will be passed
as the first parameter to the function.
If a function of this form is defined and null, the shell and
processes spawned by it will ignore SIGNAL.
The return status from the function is handled specially. If it is
zero, the signal is assumed to have been handled, and execution
continues normally. Otherwise, the shell will behave as
interrupted except that the return status of the trap is retained.
Programs terminated by uncaught signals typically return the
status 128 plus the signal number. Hence the following causes the
handler for SIGINT to print a message, then mimic the usual effect
of the signal.
TRAPINT() {
print "Caught SIGINT, aborting."
return $(( 128 + $1 ))
}
The functions TRAPZERR, TRAPDEBUG and TRAPEXIT are never executed
inside other traps.
TRAPDEBUG
If the option DEBUG_BEFORE_CMD is set (as it is by default),
executed before each command; otherwise executed after each
command. See the description of the trap builtin in *Note Shell
Builtin Commands:: for details of additional features provided in
debug traps.
TRAPEXIT
Executed when the shell exits, or when the current function exits
if defined inside a function. The value of $? at the start of
execution is the exit status of the shell or the return status of
the function exiting.
TRAPZERR
Executed whenever a command has a non-zero exit status. However,
the function is not executed if the command occurred in a sublist
followed by `&&' or `||'; only the final command in a sublist of
this type causes the trap to be executed. The function TRAPERR
acts the same as TRAPZERR on systems where there is no SIGERR
(this is the usual case).
The functions beginning `TRAP' may alternatively be defined with the
trap builtin: this may be preferable for some uses, as they are then
run in the environment of the calling process, rather than in their own
function environment. Apart from the difference in calling procedure
and the fact that the function form appears in lists of functions, the
forms
TRAPNAL() {
# code
}
and
trap '
# code
' NAL
are equivalent.
File: zsh.info, Node: Jobs & Signals, Next: Arithmetic Evaluation, Prev: Functions, Up: Top
10 Jobs & Signals
*****************
10.1 Jobs
=========
If the MONITOR option is set, an interactive shell associates a _job_
with each pipeline. It keeps a table of current jobs, printed by the
jobs command, and assigns them small integer numbers. When a job is
started asynchronously with `&', the shell prints a line to standard
error which looks like:
[1] 1234
indicating that the job which was started asynchronously was job number
1 and had one (top-level) process, whose process ID was 1234.
If a job is started with `&|' or `&!', then that job is immediately
disowned. After startup, it does not have a place in the job table,
and is not subject to the job control features described here.
If you are running a job and wish to do something else you may hit the
key ^Z (control-Z) which sends a TSTP signal to the current job: this
key may be redefined by the susp option of the external stty command. The
shell will then normally indicate that the job has been `suspended',
and print another prompt. You can then manipulate the state of this
job, putting it in the background with the bg command, or run some other
commands and then eventually bring the job back into the foreground with the
foreground command fg. A ^Z takes effect immediately and is like an
interrupt in that pending output and unread input are discarded when it
is typed.
A job being run in the background will suspend if it tries to read from
the terminal. Background jobs are normally allowed to produce output,
but this can be disabled by giving the command `stty tostop'. If you
set this tty option, then background jobs will suspend when they try to
produce output like they do when they try to read input.
When a command is suspended and continued later with the fg or wait
builtins, zsh restores tty modes that were in effect when it was
suspended. This (intentionally) does not apply if the command is
continued via `kill -CONT', nor when it is continued with bg.
There are several ways to refer to jobs in the shell. A job can be
referred to by the process ID of any process of the job or by one of
the following:
%NUMBER
The job with the given number.
%STRING
Any job whose command line begins with STRING.
%?STRING
Any job whose command line contains STRING.
%%
Current job.
%+
Equivalent to `%%'.
%-
Previous job.
The shell learns immediately whenever a process changes state. It
normally informs you whenever a job becomes blocked so that no further
progress is possible. If the NOTIFY option is not set, it waits until
just before it prints a prompt before it informs you. All such
notifications are sent directly to the terminal, not to the standard
output or standard error.
When the monitor mode is on, each background job that completes
triggers any trap set for CHLD.
When you try to leave the shell while jobs are running or suspended,
you will be warned that `You have suspended (running) jobs'. You may
use the jobs command to see what they are. If you do this or
immediately try to exit again, the shell will not warn you a second
time; the suspended jobs will be terminated, and the running jobs will
be sent a SIGHUP signal, if the HUP option is set.
To avoid having the shell terminate the running jobs, either use the
`nohup' command (see man page nohup(1)) or the disown builtin.
10.2 Signals
============
The INT and QUIT signals for an invoked command are ignored if the
command is followed by `&' and the MONITOR option is not active. The
shell itself always ignores the QUIT signal. Otherwise, signals have
the values inherited by the shell from its parent (but see the TRAPNAL
special functions in *Note Functions::).
File: zsh.info, Node: Arithmetic Evaluation, Next: Conditional Expressions, Prev: Jobs & Signals, Up: Top
11 Arithmetic Evaluation
************************
The shell can perform integer and floating point arithmetic, either
using the builtin let, or via a substitution of the form $((...)). For
integers, the shell is usually compiled to use 8-byte precision where
this is available, otherwise precision is 4 bytes. This can be tested,
for example, by giving the command `print - $(( 12345678901 ))'; if the
number appears unchanged, the precision is at least 8 bytes. Floating
point arithmetic always uses the `double' type with whatever
corresponding precision is provided by the compiler and the library.
The let builtin command takes arithmetic expressions as arguments; each
is evaluated separately. Since many of the arithmetic operators, as
well as spaces, require quoting, an alternative form is provided: for
any command which begins with a `((', all the characters until a
matching `))' are treated as a quoted expression and arithmetic
expansion performed as for an argument of let. More precisely,
`((...))' is equivalent to `let "..."'. The return status is 0 if the
arithmetic value of the expression is non-zero, 1 if it is zero, and 2
if an error occurred.
For example, the following statement
(( val = 2 + 1 ))
is equivalent to
let "val = 2 + 1"
both assigning the value 3 to the shell variable val and returning a
zero status.
Integers can be in bases other than 10. A leading `0x' or `0X' denotes
hexadecimal. Integers may also be of the form `BASE#N', where BASE is
a decimal number between two and thirty-six representing the arithmetic
base and N is a number in that base (for example, `16#ff' is 255 in
hexadecimal). The BASE# may also be omitted, in which case base 10 is
used. For backwards compatibility the form `[BASE]N' is also accepted.
It is also possible to specify a base to be used for output in the form
`[#BASE]', for example `[#16]'. This is used when outputting
arithmetical substitutions or when assigning to scalar parameters, but
an explicitly defined integer or floating point parameter will not be
affected. If an integer variable is implicitly defined by an
arithmetic expression, any base specified in this way will be set as the
variable's output arithmetic base as if the option `-i BASE' to the
typeset builtin had been used. The expression has no precedence and if
it occurs more than once in a mathematical expression, the last
encountered is used. For clarity it is recommended that it appear at
the beginning of an expression. As an example:
typeset -i 16 y
print $(( [#8] x = 32, y = 32 ))
print $x $y
outputs first `8#40', the rightmost value in the given output base, and
then `8#40 16#20', because y has been explicitly declared to have
output base 16, while x (assuming it does not already exist) is
implicitly typed by the arithmetic evaluation, where it acquires the
output base 8.
If the C_BASES option is set, hexadecimal numbers in the standard C
format, for example 0xFF instead of the usual `16#FF'. If the option
OCTAL_ZEROES is also set (it is not by default), octal numbers will be
treated similarly and hence appear as `077' instead of `8#77'. This
option has no effect on the output of bases other than hexadecimal and
octal, and these formats are always understood on input.
When an output base is specified using the `[#BASE]' syntax, an
appropriate base prefix will be output if necessary, so that the value
output is valid syntax for input. If the # is doubled, for example
`[##16]', then no base prefix is output.
Floating point constants are recognized by the presence of a decimal
point or an exponent. The decimal point may be the first character of
the constant, but the exponent character e or E may not, as it will be
taken for a parameter name.
An arithmetic expression uses nearly the same syntax and associativity
of expressions as in C.
In the native mode of operation, the following operators are supported
(listed in decreasing order of precedence):
+ - ! ~ ++ -
unary plus/minus, logical NOT, complement, {pre,post}{in,de}crement
<< >>
bitwise shift left, right
&
bitwise AND
^
bitwise XOR
|
bitwise OR
**
exponentiation
* / %
multiplication, division, modulus (remainder)
+ -
addition, subtraction
< > <= >=
comparison
== !=
equality and inequality
&&
logical AND
|| ^^
logical OR, XOR
? :
ternary operator
= += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
assignment
,
comma operator
The operators `&&', `||', `&&=', and `||=' are short-circuiting, and
only one of the latter two expressions in a ternary operator is
evaluated. Note the precedence of the bitwise AND, OR, and XOR
operators.
With the option C_PRECEDENCES the precedences (but no other properties)
of the operators are altered to be the same as those in most other
languages that support the relevant operators:
+ - ! ~ ++ -
unary plus/minus, logical NOT, complement, {pre,post}{in,de}crement
**
exponentiation
* / %
multiplication, division, modulus (remainder)
+ -
addition, subtraction
<< >>
bitwise shift left, right
< > <= >=
comparison
== !=
equality and inequality
&
bitwise AND
^
bitwise XOR
|
bitwise OR
&&
logical AND
^^
logical XOR
||
logical OR
? :
ternary operator
= += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
assignment
,
comma operator
Note the precedence of exponentiation in both cases is below that of
unary operators, hence `-3**2' evaluates as `9', not -9. Use
parentheses where necessary: `-(3**2)'. This is for compatibility with
other shells.
Mathematical functions can be called with the syntax `FUNC(ARGS)',
where the function decides if the ARGS is used as a string or a
comma-separated list of arithmetic expressions. The shell currently
defines no mathematical functions by default, but the module
zsh/mathfunc may be loaded with the zmodload builtin to provide
standard floating point mathematical functions.
An expression of the form `##X' where X is any character sequence such
as `a', `^A', or `\M-\C-x' gives the value of this character and an
expression of the form `#FOO' gives the value of the first character of
the contents of the parameter FOO. Character values are according to
the character set used in the current locale; for multibyte character
handling the option MULTIBYTE must be set. Note that this form is
different from `$#FOO', a standard parameter substitution which gives
the length of the parameter FOO. `#\' is accepted instead of `##', but
its use is deprecated.
Named parameters and subscripted arrays can be referenced by name
within an arithmetic expression without using the parameter expansion
syntax. For example,
((val2 = val1 * 2))
assigns twice the value of $val1 to the parameter named val2.
An internal integer representation of a named parameter can be
specified with the integer builtin. Arithmetic evaluation is performed
on the value of each assignment to a named parameter declared integer
in this manner. Assigning a floating point number to an integer
results in rounding down to the next integer.
Likewise, floating point numbers can be declared with the float
builtin; there are two types, differing only in their output format, as
described for the typeset builtin. The output format can be bypassed
by using arithmetic substitution instead of the parameter substitution,
i.e. `${FLOAT}' uses the defined format, but `$((FLOAT))' uses a
generic floating point format.
Promotion of integer to floating point values is performed where
necessary. In addition, if any operator which requires an integer
(`~', `&', `|', `^', `%', `<<', `>>' and their equivalents with
assignment) is given a floating point argument, it will be silently
rounded down to the next integer.
Scalar variables can hold integer or floating point values at different
times; there is no memory of the numeric type in this case.
If a variable is first assigned in a numeric context without previously
being declared, it will be implicitly typed as integer or float and
retain that type either until the type is explicitly changed or until
the end of the scope. This can have unforeseen consequences. For
example, in the loop
for (( f = 0; f < 1; f += 0.1 )); do
# use $f
done
if f has not already been declared, the first assignment will cause it
to be created as an integer, and consequently the operation `f += 0.1'
will always cause the result to be truncated to zero, so that the loop
will fail. A simple fix would be to turn the initialization into `f =
0.0'. It is therefore best to declare numeric variables with explicit
types.
File: zsh.info, Node: Conditional Expressions, Next: Prompt Expansion, Prev: Arithmetic Evaluation, Up: Top
12 Conditional Expressions
**************************
A _conditional expression_ is used with the [[ compound command to test
attributes of files and to compare strings. Each expression can be
constructed from one or more of the following unary or binary
expressions:
-a FILE
true if FILE exists.
-b FILE
true if FILE exists and is a block special file.
-c FILE
true if FILE exists and is a character special file.
-d FILE
true if FILE exists and is a directory.
-e FILE
true if FILE exists.
-f FILE
true if FILE exists and is a regular file.
-g FILE
true if FILE exists and has its setgid bit set.
-h FILE
true if FILE exists and is a symbolic link.
-k FILE
true if FILE exists and has its sticky bit set.
-n STRING
true if length of STRING is non-zero.
-o OPTION
true if option named OPTION is on. OPTION may be a single
character, in which case it is a single letter option name. (See
*Note Specifying Options::.)
-p FILE
true if FILE exists and is a FIFO special file (named pipe).
-r FILE
true if FILE exists and is readable by current process.
-s FILE
true if FILE exists and has size greater than zero.
-t FD
true if file descriptor number FD is open and associated with a
terminal device. (note: FD is not optional)
-u FILE
true if FILE exists and has its setuid bit set.
-w FILE
true if FILE exists and is writable by current process.
-x FILE
true if FILE exists and is executable by current process. If FILE
exists and is a directory, then the current process has permission
to search in the directory.
-z STRING
true if length of STRING is zero.
-L FILE
true if FILE exists and is a symbolic link.
-O FILE
true if FILE exists and is owned by the effective user ID of this
process.
-G FILE
true if FILE exists and its group matches the effective group ID
of this process.
-S FILE
true if FILE exists and is a socket.
-N FILE
true if FILE exists and its access time is not newer than its
modification time.
FILE1 -nt FILE2
true if FILE1 exists and is newer than FILE2.
FILE1 -ot FILE2
true if FILE1 exists and is older than FILE2.
FILE1 -ef FILE2
true if FILE1 and FILE2 exist and refer to the same file.
STRING = PATTERN
STRING == PATTERN
true if STRING matches PATTERN. The `==' form is the preferred
one. The `=' form is for backward compatibility and should be
considered obsolete.
STRING != PATTERN
true if STRING does not match PATTERN.
STRING =~ REGEXP
true if STRING matches the regular expression REGEXP. If the
option RE_MATCH_PCRE is set REGEXP is tested as a PCRE regular
expression using the zsh/pcre module, else it is tested as a POSIX
extended regular expression using the zsh/regex module. Upon
successful match, some variables will be updated; no variables are
changed if the matching fails. If the option BASH_REMATCH is set
the array BASH_REMATCH is set to the substring that matched the
pattern followed by the substrings that matched parenthesised
subexpressions within the pattern; otherwise, the scalar parameter
MATCH is set to the substring that matched the pattern and and the
array match to the substrings that matched parenthesised
subexpressions.
STRING1 < STRING2
true if STRING1 comes before STRING2 based on ASCII value of their
characters.
STRING1 > STRING2
true if STRING1 comes after STRING2 based on ASCII value of their
characters.
EXP1 -eq EXP2
true if EXP1 is numerically equal to EXP2.
EXP1 -ne EXP2
true if EXP1 is numerically not equal to EXP2.
EXP1 -lt EXP2
true if EXP1 is numerically less than EXP2.
EXP1 -gt EXP2
true if EXP1 is numerically greater than EXP2.
EXP1 -le EXP2
true if EXP1 is numerically less than or equal to EXP2.
EXP1 -ge EXP2
true if EXP1 is numerically greater than or equal to EXP2.
( EXP )
true if EXP is true.
! EXP
true if EXP is false.
EXP1 && EXP2
true if EXP1 and EXP2 are both true.
EXP1 || EXP2
true if either EXP1 or EXP2 is true.
Normal shell expansion is performed on the FILE, STRING and PATTERN
arguments, but the result of each expansion is constrained to be a
single word, similar to the effect of double quotes. However, pattern
metacharacters are active for the PATTERN arguments; the patterns are
the same as those used for filename generation, see *Note Filename
Generation::, but there is no special behaviour of `/' nor initial
dots, and no glob qualifiers are allowed.
In each of the above expressions, if FILE is of the form `/dev/fd/N',
where N is an integer, then the test applied to the open file whose
descriptor number is N, even if the underlying system does not support
the /dev/fd directory.
In the forms which do numeric comparison, the expressions EXP undergo
arithmetic expansion as if they were enclosed in $((...)).
For example, the following:
[[ ( -f foo || -f bar ) && $report = y* ]] && print File exists.
tests if either file foo or file bar exists, and if so, if the value of
the parameter report begins with `y'; if the complete condition is
true, the message `File exists.' is printed.
File: zsh.info, Node: Prompt Expansion, Next: Expansion, Prev: Conditional Expressions, Up: Top
13 Prompt Expansion
*******************
13.1 Expansion of Prompt Sequences
==================================
Prompt sequences undergo a special form of expansion. This type of
expansion is also available using the -P option to the print builtin.
If the PROMPT_SUBST option is set, the prompt string is first subjected
to _parameter expansion_, _command substitution_ and _arithmetic
expansion_. See *Note Expansion::.
Certain escape sequences may be recognised in the prompt string.
If the PROMPT_BANG option is set, a `!' in the prompt is replaced by
the current history event number. A literal `!' may then be
represented as `!!'.
If the PROMPT_PERCENT option is set, certain escape sequences that
start with `%' are expanded. Many escapes are followed by a single
character, although some of these take an optional integer argument that
should appear between the `%' and the next character of the sequence.
More complicated escape sequences are available to provide conditional
expansion.
13.2 Simple Prompt Escapes
==========================
13.2.1 Special characters
-------------------------
%%
A `%'.
%)
A `)'.
13.2.2 Login information
------------------------
%l
The line (tty) the user is logged in on, without `/dev/' prefix.
If the name starts with `/dev/tty', that prefix is stripped.
%M
The full machine hostname.
%m
The hostname up to the first `.'. An integer may follow the `%'
to specify how many components of the hostname are desired. With
a negative integer, trailing components of the hostname are shown.
%n
$USERNAME.
%y
The line (tty) the user is logged in on, without `/dev/' prefix.
This does not treat `/dev/tty' names specially.
13.2.3 Shell state
------------------
%#
A `#' if the shell is running with privileges, a `%' if not.
Equivalent to `%(!.#.%%)'. The definition of `privileged', for
these purposes, is that either the effective user ID is zero, or,
if POSIX.1e capabilities are supported, that at least one
capability is raised in either the Effective or Inheritable
capability vectors.
%?
The return status of the last command executed just before the
prompt.
%_
The status of the parser, i.e. the shell constructs (like `if' and
`for') that have been started on the command line. If given an
integer number that many strings will be printed; zero or negative
or no integer means print as many as there are. This is most
useful in prompts PS2 for continuation lines and PS4 for debugging
with the XTRACE option; in the latter case it will also work
non-interactively.
%d
%/
Present working directory ($PWD). If an integer follows the `%',
it specifies a number of trailing components of $PWD to show; zero
means the whole path. A negative integer specifies leading
components, i.e. %-1d specifies the first component.
%~
As %d and %/, but if $PWD has a named directory as its prefix,
that part is replaced by a `~' followed by the name of the
directory. If it starts with $HOME, that part is replaced by a
`~'.
%h
%!
Current history event number.
%i
The line number currently being executed in the script, sourced
file, or shell function given by %N. This is most useful for
debugging as part of $PS4.
%I
The line number currently being executed in the file %x. This is
similar to %i, but the line number is always a line number in the
file where the code was defined, even if the code is a shell
function.
%j
The number of jobs.
%L
The current value of $SHLVL.
%N
The name of the script, sourced file, or shell function that zsh is
currently executing, whichever was started most recently. If
there is none, this is equivalent to the parameter $0. An integer
may follow the `%' to specify a number of trailing path components
to show; zero means the full path. A negative integer specifies
leading components.
%x
The name of the file containing the source code currently being
executed. This behaves as %N except that function and eval command
names are not shown, instead the file where they were defined.
%c
%.
%C
Trailing component of $PWD. An integer may follow the `%' to get
more than one component. Unless `%C' is used, tilde contraction
is performed first. These are deprecated as %c and %C are
equivalent to %1~ and %1/, respectively, while explicit positive
integers have the same effect as for the latter two sequences.
13.2.4 Date and time
--------------------
%D
The date in YY-MM-DD format.
%T
Current time of day, in 24-hour format.
%t
%@
Current time of day, in 12-hour, am/pm format.
%*
Current time of day in 24-hour format, with seconds.
%w
The date in DAY-DD format.
%W
The date in MM/DD/YY format.
%D{STRING}
STRING is formatted using the strftime function. See man page
strftime(3) for more details. Various zsh extensions provide
numbers with no leading zero or space if the number is a single
digit:
%f
a day of the month
%K
the hour of the day on the 24-hour clock
%L
the hour of the day on the 12-hour clock
The GNU extension that a `-' between the % and the format
character causes a leading zero or space to be stripped is handled
directly by the shell for the format characters d, f, H, k, l, m,
M, S and y; any other format characters are provided to strftime()
with any leading `-', present, so the handling is system
dependent. Further GNU extensions are not supported at present.
13.2.5 Visual effects
---------------------
%B (%b)
Start (stop) boldface mode.
%E
Clear to end of line.
%U (%u)
Start (stop) underline mode.
%S (%s)
Start (stop) standout mode.
%F (%f)
Start (stop) using a different foreground colour, if supported by
the terminal. The colour may be specified two ways: either as a
numeric argument, as normal, or by a sequence in braces following
the %F, for example %F{red}. In the latter case the values
allowed are as described for the fg zle_highlight attribute; *Note
Character Highlighting::. This means that numeric colours are
allowed in the second format also.
%K (%k)
Start (stop) using a different bacKground colour. The syntax is
identical to that for %F and %f.
%{...%}
Include a string as a literal escape sequence. The string within
the braces should not change the cursor position. Brace pairs can
nest.
A positive numeric argument between the % and the { is treated as
described for %G below.
%G
Within a %{...%} sequence, include a `glitch': that is, assume
that a single character width will be output. This is useful when
outputting characters that otherwise cannot be correctly handled
by the shell, such as the alternate character set on some
terminals. The characters in question can be included within a
%{...%} sequence together with the appropriate number of %G
sequences to indicate the correct width. An integer between the
`%' and `G' indicates a character width other than one. Hence
%{SEQ%2G%} outputs SEQ and assumes it takes up the width of two
standard characters.
Multiple uses of %G accumulate in the obvious fashion; the position
of the %G is unimportant. Negative integers are not handled.
Note that when prompt truncation is in use it is advisable to
divide up output into single characters within each %{...%} group
so that the correct truncation point can be found.
13.3 Conditional Substrings in Prompts
======================================
%v
The value of the first element of the psvar array parameter.
Following the `%' with an integer gives that element of the array.
Negative integers count from the end of the array.
%(X.TRUE-TEXT.FALSE-TEXT)
Specifies a ternary expression. The character following the X is
arbitrary; the same character is used to separate the text for the
`true' result from that for the `false' result. This separator
may not appear in the TRUE-TEXT, except as part of a %-escape
sequence. A `)' may appear in the FALSE-TEXT as `%)'. TRUE-TEXT
and FALSE-TEXT may both contain arbitrarily-nested escape
sequences, including further ternary expressions.
The left parenthesis may be preceded or followed by a positive
integer N, which defaults to zero. A negative integer will be
multiplied by -1. The test character X may be any of the
following:
!
True if the shell is running with privileges.
#
True if the effective uid of the current process is N.
?
True if the exit status of the last command was N.
_
True if at least N shell constructs were started.
C
/
True if the current absolute path has at least N elements
relative to the root directory, hence / is counted as 0
elements.
c
.
~
True if the current path, with prefix replacement, has at
least N elements relative to the root directory, hence / is
counted as 0 elements.
D
True if the month is equal to N (January = 0).
d
True if the day of the month is equal to N.
g
True if the effective gid of the current process is N.
j
True if the number of jobs is at least N.
L
True if the SHLVL parameter is at least N.
l
True if at least N characters have already been printed on
the current line.
S
True if the SECONDS parameter is at least N.
T
True if the time in hours is equal to N.
t
True if the time in minutes is equal to N.
v
True if the array psvar has at least N elements.
V
True if element N of the array psvar is set and non-empty.
w
True if the day of the week is equal to N (Sunday = 0).
%<STRING<
%>STRING>
%[XSTRING]
Specifies truncation behaviour for the remainder of the prompt
string. The third, deprecated, form is equivalent to `%XSTRINGX',
i.e. X may be `<' or `>'. The numeric argument, which in the
third form may appear immediately after the `[', specifies the
maximum permitted length of the various strings that can be
displayed in the prompt. The STRING will be displayed in place of
the truncated portion of any string; note this does not undergo
prompt expansion.
The forms with `<' truncate at the left of the string, and the
forms with `>' truncate at the right of the string. For example,
if the current directory is `/home/pike', the prompt `%8<..<%/'
will expand to `..e/pike'. In this string, the terminating
character (`<', `>' or `]'), or in fact any character, may be
quoted by a preceding `\'; note when using print -P, however, that
this must be doubled as the string is also subject to standard
print processing, in addition to any backslashes removed by a
double quoted string: the worst case is therefore `print -P
"%<\\\\<<..."'.
If the STRING is longer than the specified truncation length, it
will appear in full, completely replacing the truncated string.
The part of the prompt string to be truncated runs to the end of
the string, or to the end of the next enclosing group of the `%('
construct, or to the next truncation encountered at the same
grouping level (i.e. truncations inside a `%(' are separate), which
ever comes first. In particular, a truncation with argument zero
(e.g. `%<<') marks the end of the range of the string to be
truncated while turning off truncation from there on. For example,
the prompt '%10<...<%~%<<%# ' will print a truncated
representation of the current directory, followed by a `%' or `#',
followed by a space. Without the `%<<', those two characters
would be included in the string to be truncated.
File: zsh.info, Node: Expansion, Next: Parameters, Prev: Prompt Expansion, Up: Top
14 Expansion
************
The following types of expansions are performed in the indicated
order in five steps:
_History Expansion_
This is performed only in interactive shells.
_Alias Expansion_
Aliases are expanded immediately before the command line is parsed
as explained in *Note Aliasing::.
_Process Substitution_
_Parameter Expansion_
_Command Substitution_
_Arithmetic Expansion_
_Brace Expansion_
These five are performed in one step in left-to-right fashion.
After these expansions, all unquoted occurrences of the characters
`\', `'' and `"' are removed.
_Filename Expansion_
If the SH_FILE_EXPANSION option is set, the order of expansion is
modified for compatibility with `sh' and `ksh'. In that case
_filename expansion_ is performed immediately after _alias
expansion_, preceding the set of five expansions mentioned above.
_Filename Generation_
This expansion, commonly referred to as `globbing', is always done
last.
The following sections explain the types of expansion in detail.
* Menu:
* History Expansion::
* Process Substitution::
* Parameter Expansion::
* Command Substitution::
* Arithmetic Expansion::
* Brace Expansion::
* Filename Expansion::
* Filename Generation::
File: zsh.info, Node: History Expansion, Next: Process Substitution, Up: Expansion
14.1 History Expansion
======================
History expansion allows you to use words from previous command lines
in the command line you are typing. This simplifies spelling
corrections and the repetition of complicated commands or arguments. Immediately
before execution, each command is saved in the history list, the size
of which is controlled by the HISTSIZE parameter. The one most recent
command is always retained in any case. Each saved command in the
history list is called a history _event_ and is assigned a number,
beginning with 1 (one) when the shell starts up. The history number
that you may see in your prompt (see *Note Prompt Expansion::) is the
number that is to be assigned to the _next_ command.
* Menu:
* Overview::
* Event Designators::
* Word Designators::
* Modifiers::
File: zsh.info, Node: Overview, Next: Event Designators, Up: History Expansion
14.1.1 Overview
---------------
A history expansion begins with the first character of the histchars
parameter, which is `!' by default, and may occur anywhere on the
command line; history expansions do not nest. The `!' can be escaped
with `\' or can be enclosed between a pair of single quotes ('') to
suppress its special meaning. Double quotes will _not_ work for this.
Following this history character is an optional event designator (*Note
Event Designators::) and then an optional word designator (*Note Word
Designators::); if neither of these designators is present, no history
expansion occurs.
Input lines containing history expansions are echoed after being
expanded, but before any other expansions take place and before the
command is executed. It is this expanded form that is recorded as the
history event for later references.
By default, a history reference with no event designator refers to the
same event as any preceding history reference on that command line; if
it is the only history reference in a command, it refers to the previous
command. However, if the option CSH_JUNKIE_HISTORY is set, then every
history reference with no event specification _always_ refers to the
previous command.
For example, `!' is the event designator for the previous command, so
`!!:1' always refers to the first word of the previous command, and
`!!$' always refers to the last word of the previous command. With
CSH_JUNKIE_HISTORY set, then `!:1' and `!$' function in the same manner
as `!!:1' and `!!$', respectively. Conversely, if CSH_JUNKIE_HISTORY
is unset, then `!:1' and `!$' refer to the first and last words,
respectively, of the same event referenced by the nearest other history
reference preceding them on the current command line, or to the
previous command if there is no preceding reference.
The character sequence `^FOO^BAR' (where `^' is actually the second
character of the histchars parameter) repeats the last command,
replacing the string FOO with BAR. More precisely, the sequence
`^FOO^BAR^' is synonymous with `!!:s^FOO^BAR^', hence other modifiers
(see *Note Modifiers::) may follow the final `^'. In particular,
`^FOO^BAR:G' performs a global substitution.
If the shell encounters the character sequence `!"' in the input, the
history mechanism is temporarily disabled until the current list (see
*Note Shell Grammar::) is fully parsed. The `!"' is removed from the
input, and any subsequent `!' characters have no special significance.
A less convenient but more comprehensible form of command history
support is provided by the fc builtin.
File: zsh.info, Node: Event Designators, Next: Word Designators, Prev: Overview, Up: History Expansion
14.1.2 Event Designators
------------------------
An event designator is a reference to a command-line entry in the
history list. In the list below, remember that the initial `!' in each
item may be changed to another character by setting the histchars
parameter.
!
Start a history expansion, except when followed by a blank,
newline, `=' or `('. If followed immediately by a word designator
(*Note Word Designators::), this forms a history reference with no
event designator (*Note Overview::).
!!
Refer to the previous command. By itself, this expansion repeats
the previous command.
!N
Refer to command-line N.
!-N
Refer to the current command-line minus N.
!STR
Refer to the most recent command starting with STR.
!?STR[?]
Refer to the most recent command containing STR. The trailing `?'
is necessary if this reference is to be followed by a modifier or
followed by any text that is not to be considered part of STR.
!#
Refer to the current command line typed in so far. The line is
treated as if it were complete up to and including the word before
the one with the `!#' reference.
!{...}
Insulate a history reference from adjacent characters (if
necessary).
File: zsh.info, Node: Word Designators, Next: Modifiers, Prev: Event Designators, Up: History Expansion
14.1.3 Word Designators
-----------------------
A word designator indicates which word or words of a given command line
are to be included in a history reference. A `:' usually separates the
event specification from the word designator. It may be omitted only
if the word designator begins with a `^', `$', `*', `-' or `%'. Word
designators include:
0
The first input word (command).
N
The Nth argument.
^
The first argument. That is, 1.
$
The last argument.
%
The word matched by (the most recent) ?STR search.
X-Y
A range of words; X defaults to 0.
*
All the arguments, or a null value if there are none.
X*
Abbreviates `X-$'.
X-
Like `X*' but omitting word $.
Note that a `%' word designator works only when used in one of `!%',
`!:%' or `!?STR?:%', and only when used after a !? expansion (possibly
in an earlier command). Anything else results in an error, although
the error may not be the most obvious one.
File: zsh.info, Node: Modifiers, Prev: Word Designators, Up: History Expansion
14.1.4 Modifiers
----------------
After the optional word designator, you can add a sequence of one or
more of the following modifiers, each preceded by a `:'. These
modifiers also work on the result of _filename generation_ and
_parameter expansion_, except where noted.
a
Turn a file name into an absolute path: prepends the current
directory, if necessary, and resolves any use of `..' and `.' in
the path. Note that the transformation takes place even if the
file or any intervening directories do not exist.
A
As `a', but also resolve use of symbolic links where possible.
Note that resolution of `..' occurs _before_ resolution of symbolic
links. This call is equivalent to a unless your system has the
realpath system call (modern systems do).
c
Resolve a command name into an absolute path by searching the
command path given by the PATH variable. This does not work for
commands containing directory parts. Note also that this does not
usually work as a glob qualifier unless a file of the same name is
found in the current directory.
e
Remove all but the extension.
h
Remove a trailing pathname component, leaving the head. This works
like `dirname'.
l
Convert the words to all lowercase.
p
Print the new command but do not execute it. Only works with
history expansion.
q
Quote the substituted words, escaping further substitutions. Works
with history expansion and parameter expansion, though for
parameters it is only useful if the resulting text is to be
re-evaluated such as by eval.
Q
Remove one level of quotes from the substituted words.
r
Remove a filename extension of the form `.XXX', leaving the root
name.
s/L/R[/]
Substitute R for L as described below. The substitution is done
only for the first string that matches L. For arrays and for
filename generation, this applies to each word of the expanded
text. See below for further notes on substitutions.
The forms `gs/L/R' and `s/L/R/:G' perform global substitution,
i.e. substitute every occurrence of R for L. Note that the g or
:G must appear in exactly the position shown.
&
Repeat the previous s substitution. Like s, may be preceded
immediately by a g. In parameter expansion the & must appear
inside braces, and in filename generation it must be quoted with a
backslash.
t
Remove all leading pathname components, leaving the tail. This
works like `basename'.
u
Convert the words to all uppercase.
x
Like q, but break into words at whitespace. Does not work with
parameter expansion.
The s/l/r/ substitution works as follows. By default the left-hand
side of substitutions are not patterns, but character strings. Any
character can be used as the delimiter in place of `/'. A backslash
quotes the delimiter character. The character `&', in the
right-hand-side R, is replaced by the text from the left-hand-side L.
The `&' can be quoted with a backslash. A null L uses the previous
string either from the previous L or from the contextual scan string S
from `!?S'. You can omit the rightmost delimiter if a newline
immediately follows R; the rightmost `?' in a context scan can
similarly be omitted. Note the same record of the last L and R is
maintained across all forms of expansion.
If the option HIST_SUBST_PATTERN is set, L is treated as a pattern of
the usual form described in *Note Filename Generation::. This can be
used in all the places where modifiers are available; note, however,
that in globbing qualifiers parameter substitution has already taken
place, so parameters in the replacement string should be quoted to
ensure they are replaced at the correct time. Note also that
complicated patterns used in globbing qualifiers may need the extended
glob qualifier notation (#q:s/.../.../) in order for the shell to
recognize the expression as a glob qualifier. Further, note that bad
patterns in the substitution are not subject to the NO_BAD_PATTERN
option so will cause an error.
When HIST_SUBST_PATTERN is set, L may start with a # to indicate that
the pattern must match at the start of the string to be substituted,
and a % may appear at the start or after an # to indicate that the
pattern must match at the end of the string to be substituted. The %
or # may be quoted with two backslashes.
For example, the following piece of filename generation code with the
EXTENDED_GLOB option:
print *.c(#q:s/#%(#b)s(*).c/'S${match[1]}.C'/)
takes the expansion of *.c and applies the glob qualifiers in the
(#q...) expression, which consists of a substitution modifier anchored
to the start and end of each word (#%). This turns on backreferences
((#b)), so that the parenthesised subexpression is available in the
replacement string as ${match[1]}. The replacement string is quoted so
that the parameter is not substituted before the start of filename
generation.
The following f, F, w and W modifiers work only with parameter
expansion and filename generation. They are listed here to provide a
single point of reference for all modifiers.
f
Repeats the immediately (without a colon) following modifier until
the resulting word doesn't change any more.
F:EXPR:
Like f, but repeats only N times if the expression EXPR evaluates
to N. Any character can be used instead of the `:'; if `(', `[',
or `{' is used as the opening delimiter, the closing delimiter
should be ')', `]', or `}', respectively.
w
Makes the immediately following modifier work on each word in the
string.
W:SEP:
Like w but words are considered to be the parts of the string that
are separated by SEP. Any character can be used instead of the
`:'; opening parentheses are handled specially, see above.
File: zsh.info, Node: Process Substitution, Next: Parameter Expansion, Prev: History Expansion, Up: Expansion
14.2 Process Substitution
=========================
Each part of a command argument that takes the form `<(LIST)',
`>(LIST)' or `=(LIST)' is subject to process substitution. The
expression may be preceeded or followed by other strings except that,
to prevent clashes with commonly occurring strings and patterns, the
last form must occur at the start of a command argument, and the forms
are only expanded when first parsing command or assignment arguments.
Process substitutions may be used following redirection operators; in
this case, the substitution must appear with no trailing string.
In the case of the < or > forms, the shell runs the commands in LIST
asynchronously. If the system supports the /dev/fd mechanism, the
command argument is the name of the device file corresponding to a file
descriptor; otherwise, if the system supports named pipes (FIFOs), the
command argument will be a named pipe. If the form with > is selected
then writing on this special file will provide input for LIST. If < is
used, then the file passed as an argument will be connected to the
output of the LIST process. For example,
paste <(cut -f1 FILE1) <(cut -f3 FILE2) |
tee >(PROCESS1) >(PROCESS2) >/dev/null
cuts fields 1 and 3 from the files FILE1 and FILE2 respectively, pastes
the results together, and sends it to the processes PROCESS1 and
PROCESS2.
If =(...) is used instead of <(...), then the file passed as an
argument will be the name of a temporary file containing the output of
the LIST process. This may be used instead of the < form for a program
that expects to lseek (see man page lseek(2)) on the input file.
There is an optimisation for substitutions of the form =(<<<ARG), where
ARG is a single-word argument to the here-string redirection <<<. This
form produces a file name containing the value of ARG after any
substitutions have been performed. This is handled entirely within the
current shell. This is effectively the reverse of the special form
$(<ARG) which treats ARG as a file name and replaces it with the file's
contents.
The = form is useful as both the /dev/fd and the named pipe
implementation of <(...) have drawbacks. In the former case, some
programmes may automatically close the file descriptor in question
before examining the file on the command line, particularly if this is
necessary for security reasons such as when the programme is running
setuid. In the second case, if the programme does not actually open
the file, the subshell attempting to read from or write to the pipe
will (in a typical implementation, different operating systems may have
different behaviour) block for ever and have to be killed explicitly.
In both cases, the shell actually supplies the information using a
pipe, so that programmes that expect to lseek (see man page lseek(2))
on the file will not work.
Also note that the previous example can be more compactly and
efficiently written (provided the MULTIOS option is set) as:
paste <(cut -f1 FILE1) <(cut -f3 FILE2) > >(PROCESS1) > >(PROCESS2)
The shell uses pipes instead of FIFOs to implement the latter two
process substitutions in the above example.
There is an additional problem with >(PROCESS); when this is attached
to an external command, the parent shell does not wait for PROCESS to
finish and hence an immediately following command cannot rely on the
results being complete. The problem and solution are the same as
described in the section _MULTIOS_ in *Note Redirection::. Hence in a
simplified version of the example above:
paste <(cut -f1 FILE1) <(cut -f3 FILE2) > >(PROCESS)
(note that no MULTIOS are involved), PROCESS will be run
asynchronously. The workaround is:
{ paste <(cut -f1 FILE1) <(cut -f3 FILE2) } > >(PROCESS)
The extra processes here are spawned from the parent shell which will
wait for their completion.
File: zsh.info, Node: Parameter Expansion, Next: Command Substitution, Prev: Process Substitution, Up: Expansion
14.3 Parameter Expansion
========================
The character `$' is used to introduce parameter expansions. See *Note
Parameters:: for a description of parameters, including arrays,
associative arrays, and subscript notation to access individual array
elements.
Note in particular the fact that words of unquoted parameters are not
automatically split on whitespace unless the option SH_WORD_SPLIT is
set; see references to this option below for more details. This is an
important difference from other shells.
In the expansions discussed below that require a pattern, the form of
the pattern is the same as that used for filename generation; see *Note
Filename Generation::. Note that these patterns, along with the
replacement text of any substitutions, are themselves subject to
parameter expansion, command substitution, and arithmetic expansion.
In addition to the following operations, the colon modifiers described
in *Note Modifiers:: in *Note History Expansion:: can be applied: for
example, ${i:s/foo/bar/} performs string substitution on the expansion
of parameter $i.
${NAME}
The value, if any, of the parameter NAME is substituted. The
braces are required if the expansion is to be followed by a
letter, digit, or underscore that is not to be interpreted as part
of NAME. In addition, more complicated forms of substitution
usually require the braces to be present; exceptions, which only
apply if the option KSH_ARRAYS is not set, are a single subscript
or any colon modifiers appearing after the name, or any of the
characters `^', `=', `~', `#' or `+' appearing before the name,
all of which work with or without braces.
If NAME is an array parameter, and the KSH_ARRAYS option is not
set, then the value of each element of NAME is substituted, one
element per word. Otherwise, the expansion results in one word
only; with KSH_ARRAYS, this is the first element of an array. No
field splitting is done on the result unless the SH_WORD_SPLIT
option is set. See also the flags = and s:STRING:.
${+NAME}
If NAME is the name of a set parameter `1' is substituted,
otherwise `0' is substituted.
${NAME-WORD}
${NAME:-WORD}
If NAME is set, or in the second form is non-null, then substitute
its value; otherwise substitute WORD. In the second form NAME may
be omitted, in which case WORD is always substituted.
${NAME+WORD}
${NAME:+WORD}
If NAME is set, or in the second form is non-null, then substitute
WORD; otherwise substitute nothing.
${NAME=WORD}
${NAME:=WORD}
${NAME::=WORD}
In the first form, if NAME is unset then set it to WORD; in the
second form, if NAME is unset or null then set it to WORD; and in
the third form, unconditionally set NAME to WORD. In all forms,
the value of the parameter is then substituted.
${NAME?WORD}
${NAME:?WORD}
In the first form, if NAME is set, or in the second form if NAME
is both set and non-null, then substitute its value; otherwise,
print WORD and exit from the shell. Interactive shells instead
return to the prompt. If WORD is omitted, then a standard message
is printed.
In any of the above expressions that test a variable and substitute an
alternate WORD, note that you can use standard shell quoting in the
WORD value to selectively override the splitting done by the
SH_WORD_SPLIT option and the = flag, but not splitting by the s:STRING:
flag.
In the following expressions, when NAME is an array and the
substitution is not quoted, or if the `(@)' flag or the NAME[@] syntax
is used, matching and replacement is performed on each array element
separately.
${NAME#PATTERN}
${NAME##PATTERN}
If the PATTERN matches the beginning of the value of NAME, then
substitute the value of NAME with the matched portion deleted;
otherwise, just substitute the value of NAME. In the first form,
the smallest matching pattern is preferred; in the second form,
the largest matching pattern is preferred.
${NAME%PATTERN}
${NAME%%PATTERN}
If the PATTERN matches the end of the value of NAME, then
substitute the value of NAME with the matched portion deleted;
otherwise, just substitute the value of NAME. In the first form,
the smallest matching pattern is preferred; in the second form,
the largest matching pattern is preferred.
${NAME:#PATTERN}
If the PATTERN matches the value of NAME, then substitute the
empty string; otherwise, just substitute the value of NAME. If
NAME is an array the matching array elements are removed (use the
`(M)' flag to remove the non-matched elements).
${NAME/PATTERN/REPL}
${NAME//PATTERN/REPL}
Replace the longest possible match of PATTERN in the expansion of
parameter NAME by string REPL. The first form replaces just the
first occurrence, the second form all occurrences. Both PATTERN
and REPL are subject to double-quoted substitution, so that
expressions like ${name/$opat/$npat} will work, but note the usual
rule that pattern characters in $opat are not treated specially
unless either the option GLOB_SUBST is set, or $opat is instead
substituted as ${~opat}.
The PATTERN may begin with a `#', in which case the PATTERN must
match at the start of the string, or `%', in which case it must
match at the end of the string, or `#%' in which case the PATTERN
must match the entire string. The REPL may be an empty string, in
which case the final `/' may also be omitted. To quote the final
`/' in other cases it should be preceded by a single backslash;
this is not necessary if the `/' occurs inside a substituted
parameter. Note also that the `#', `%' and `#% are not active if
they occur inside a substituted parameter, even at the start.
The first `/' may be preceded by a `:', in which case the match
will only succeed if it matches the entire word. Note also the
effect of the I and S parameter expansion flags below; however,
the flags M, R, B, E and N are not useful.
For example,
foo="twinkle twinkle little star" sub="t*e" rep="spy"
print ${foo//${~sub}/$rep}
print ${(S)foo//${~sub}/$rep}
Here, the `~' ensures that the text of $sub is treated as a
pattern rather than a plain string. In the first case, the longest
match for t*e is substituted and the result is `spy star', while
in the second case, the shortest matches are taken and the result
is `spy spy lispy star'.
${#SPEC}
If SPEC is one of the above substitutions, substitute the length
in characters of the result instead of the result itself. If SPEC
is an array expression, substitute the number of elements of the
result. Note that `^', `=', and `~', below, must appear to the
left of `#' when these forms are combined.
${^SPEC}
Turn on the RC_EXPAND_PARAM option for the evaluation of SPEC; if
the `^' is doubled, turn it off. When this option is set, array
expansions of the form FOO${XX}BAR, where the parameter XX is set
to (A B C), are substituted with `FOOABAR FOOBBAR FOOCBAR' instead
of the default `FOOA B CBAR'. Note that an empty array will
therefore cause all arguments to be removed.
Internally, each such expansion is converted into the equivalent
list for brace expansion. E.g., ${^var} becomes
{$var[1],$var[2],...}, and is processed as described in *Note
Brace Expansion:: below. If word splitting is also in effect the
$var[N] may themselves be split into different list elements.
${=SPEC}
Perform word splitting using the rules for SH_WORD_SPLIT during the
evaluation of SPEC, but regardless of whether the parameter
appears in double quotes; if the `=' is doubled, turn it off. This
forces parameter expansions to be split into separate words before
substitution, using IFS as a delimiter. This is done by default
in most other shells.
Note that splitting is applied to WORD in the assignment forms of
SPEC _before_ the assignment to NAME is performed. This affects
the result of array assignments with the A flag.
${~SPEC}
Turn on the GLOB_SUBST option for the evaluation of SPEC; if the
`~' is doubled, turn it off. When this option is set, the string
resulting from the expansion will be interpreted as a pattern
anywhere that is possible, such as in filename expansion and
filename generation and pattern-matching contexts like the right
hand side of the `=' and `!=' operators in conditions.
In nested substitutions, note that the effect of the ~ applies to
the result of the current level of substitution. A surrounding
pattern operation on the result may cancel it. Hence, for
example, if the parameter foo is set to *, ${~foo//\*/*.c} is
substituted by the pattern *.c, which may be expanded by filename
generation, but ${${~foo}//\*/*.c} substitutes to the string *.c,
which will not be further expanded.
If a ${...} type parameter expression or a $(...) type command
substitution is used in place of NAME above, it is expanded first and
the result is used as if it were the value of NAME. Thus it is
possible to perform nested operations: ${${foo#head}%tail} substitutes
the value of $foo with both `head' and `tail' deleted. The form with
$(...) is often useful in combination with the flags described next;
see the examples below. Each NAME or nested ${...} in a parameter
expansion may also be followed by a subscript expression as described in
*Note Array Parameters::.
Note that double quotes may appear around nested expressions, in which
case only the part inside is treated as quoted; for example,
${(f)"$(foo)"} quotes the result of $(foo), but the flag `(f)' (see
below) is applied using the rules for unquoted expansions. Note
further that quotes are themselves nested in this context; for example,
in "${(@f)"$(foo)"}", there are two sets of quotes, one surrounding the
whole expression, the other (redundant) surrounding the $(foo) as
before.
14.3.1 Parameter Expansion Flags
--------------------------------
If the opening brace is directly followed by an opening parenthesis,
the string up to the matching closing parenthesis will be taken as a
list of flags. In cases where repeating a flag is meaningful, the
repetitions need not be consecutive; for example, `(q%q%q)' means the
same thing as the more readable `(%%qqq)'. The following flags are
supported:
#
Evaluate the resulting words as numeric expressions and output the
characters corresponding to the resulting integer. Note that this
form is entirely distinct from use of the # without parentheses.
If the MULTIBYTE option is set and the number is greater than 127
(i.e. not an ASCII character) it is treated as a Unicode character.
%
Expand all % escapes in the resulting words in the same way as in
prompts (see *Note Prompt Expansion::). If this flag is given
twice, full prompt expansion is done on the resulting words,
depending on the setting of the PROMPT_PERCENT, PROMPT_SUBST and
PROMPT_BANG options.
@
In double quotes, array elements are put into separate words.
E.g., `"${(@)foo}"' is equivalent to `"${foo[@]}"' and
`"${(@)foo[1,2]}"' is the same as `"$foo[1]" "$foo[2]"'. This is
distinct from _field splitting_ by the the f, s or z flags, which
still applies within each array element.
A
Create an array parameter with `${...=...}', `${...:=...}' or
`${...::=...}'. If this flag is repeated (as in `AA'), create an
associative array parameter. Assignment is made before sorting or
padding. The NAME part may be a subscripted range for ordinary
arrays; the WORD part _must_ be converted to an array, for example
by using `${(AA)=NAME=...}' to activate field splitting, when
creating an associative array.
a
Sort in array index order; when combined with `O' sort in reverse
array index order. Note that `a' is therefore equivalent to the
default but `Oa' is useful for obtaining an array's elements in
reverse order.
c
With ${#NAME}, count the total number of characters in an array,
as if the elements were concatenated with spaces between them.
C
Capitalize the resulting words. `Words' in this case refers to
sequences of alphanumeric characters separated by
non-alphanumerics, _not_ to words that result from field splitting.
e
Perform _parameter expansion_, _command substitution_ and
_arithmetic expansion_ on the result. Such expansions can be
nested but too deep recursion may have unpredictable effects.
f
Split the result of the expansion to lines. This is a shorthand
for `ps:\n:'.
F
Join the words of arrays together using newline as a separator.
This is a shorthand for `pj:\n:'.
i
Sort case-insensitively. May be combined with `n' or `O'.
k
If NAME refers to an associative array, substitute the _keys_
(element names) rather than the values of the elements. Used with
subscripts (including ordinary arrays), force indices or keys to be
substituted even if the subscript form refers to values. However,
this flag may not be combined with subscript ranges.
L
Convert all letters in the result to lower case.
n
Sort decimal integers numerically; if the first differing
characters of two test strings are not digits, sorting is lexical.
Integers with more initial zeroes are sorted before those with
fewer or none. Hence the array `foo1 foo02 foo2 foo3 foo20 foo23'
is sorted into the order shown. May be combined with `i' or `O'.
o
Sort the resulting words in ascending order; if this appears on its
own the sorting is lexical and case-sensitive (unless the locale
renders it case-insensitive). Sorting in ascending order is the
default for other forms of sorting, so this is ignored if combined
with `a', `i' or `n'.
O
Sort the resulting words in descending order; `O' without `a', `i'
or `n' sorts in reverse lexical order. May be combined with `a',
`i' or `n' to reverse the order of sorting.
P
This forces the value of the parameter NAME to be interpreted as a
further parameter name, whose value will be used where appropriate.
Note that flags set with one of the typeset family of commands (in
particular case transformations) are not applied to the value of
NAME used in this fashion.
If used with a nested parameter or command substitution, the
result of that will be taken as a parameter name in the same way.
For example, if you have `foo=bar' and `bar=baz', the strings
${(P)foo}, ${(P)${foo}}, and ${(P)$(echo bar)} will be expanded to
`baz'.
q
Quote the resulting words with backslashes; unprintable or invalid
characters are quoted using the $'\NNN' form, with separate quotes
for each octet. If this flag is given twice, the resulting words
are quoted in single quotes and if it is given three times, the
words are quoted in double quotes; in these forms no special
handling of unprintable or invalid characters is attempted. If
the flag is given four times, the words are quoted in single quotes
preceded by a $.
Q
Remove one level of quotes from the resulting words.
t
Use a string describing the type of the parameter where the value
of the parameter would usually appear. This string consists of
keywords separated by hyphens (`-'). The first keyword in the
string describes the main type, it can be one of `scalar',
`array', `integer', `float' or `association'. The other keywords
describe the type in more detail:
local
for local parameters
left
for left justified parameters
right_blanks
for right justified parameters with leading blanks
right_zeros
for right justified parameters with leading zeros
lower
for parameters whose value is converted to all lower case
when it is expanded
upper
for parameters whose value is converted to all upper case
when it is expanded
readonly
for readonly parameters
tag
for tagged parameters
export
for exported parameters
unique
for arrays which keep only the first occurrence of duplicated
values
hide
for parameters with the `hide' flag
special
for special parameters defined by the shell
u
Expand only the first occurrence of each unique word.
U
Convert all letters in the result to upper case.
v
Used with k, substitute (as two consecutive words) both the key
and the value of each associative array element. Used with
subscripts, force values to be substituted even if the subscript
form refers to indices or keys.
V
Make any special characters in the resulting words visible.
w
With ${#NAME}, count words in arrays or strings; the s flag may be
used to set a word delimiter.
W
Similar to w with the difference that empty words between repeated
delimiters are also counted.
X
With this flag, parsing errors occurring with the Q, e and # flags
or the pattern matching forms such as `${NAME#PATTERN}' are
reported. Without the flag, errors are silently ignored.
z
Split the result of the expansion into words using shell parsing to
find the words, i.e. taking into account any quoting in the value.
Note that this is done very late, as for the `(s)' flag. So to
access single words in the result, one has to use nested
expansions as in `${${(z)foo}[2]}'. Likewise, to remove the quotes
in the resulting words one would do: `${(Q)${(z)foo}}'.
0
Split the result of the expansion on null bytes. This is a
shorthand for `ps:\0:'.
The following flags (except p) are followed by one or more arguments as
shown. Any character, or the matching pairs `(...)', `{...}', `[...]',
or `<...>', may be used in place of a colon as delimiters, but note
that when a flag takes more than one argument, a matched pair of
delimiters must surround each argument.
p
Recognize the same escape sequences as the print builtin in string
arguments to any of the flags described below that follow this
argument.
~
Force string arguments to any of the flags below that follow within
the parentheses to be treated as patterns. Compare with a ~
outside parentheses, which forces the entire substituted string to
be treated as a pattern. Hence, for example,
[[ "?" = ${(~j.|.)array} ]]
with the EXTENDED_GLOB option set succeeds if and only if $array
contains the string `?' as an element. The argument may be
repeated to toggle the behaviour; its effect only lasts to the end
of the parenthesised group.
j:STRING:
Join the words of arrays together using STRING as a separator. Note
that this occurs before field splitting by the s:STRING: flag or
the SH_WORD_SPLIT option.
l:EXPR::STRING1::STRING2:
Pad the resulting words on the left. Each word will be truncated
if required and placed in a field EXPR characters wide.
The arguments :STRING1: and :STRING2: are optional; neither, the
first, or both may be given. Note that the same pairs of
delimiters must be used for each of the three arguments. The
space to the left will be filled with STRING1 (concatenated as
often as needed) or spaces if STRING1 is not given. If both
STRING1 and STRING2 are given, string2 is inserted once directly
to the left of each word, truncated if necessary, before STRING1
is used to produce any remaining padding.
If the MULTIBYTE option is in effect, the flag m may also be
given, in which case widths will be used for the calculation of
padding; otherwise individual multibyte characters are treated as
occupying one unit of width.
IF the MULTIBYTE option is not in effect, each byte in the string
is treated as occupying one unit of width.
Control characters are always assumed to be one unit wide; this
allows the mechanism to be used for generating repetitions of
control characters.
m
Only useful together with one of the flags l or r or with the #
length operator when the MULTIBYTE option is in effect. Use the
character width reported by the system in calculating the how much
of the string it occupies or the overall length of the string.
Most printable characters have a width of one unit, however
certain Asian character sets and certain special effects use wider
characters; combining characters have zero width.
r:EXPR::STRING1::STRING2:
As l, but pad the words on the right and insert STRING2
immediately to the right of the string to be padded.
Left and right padding may be used together. In this case the
strategy is to apply left padding to the first half width of each
of the resulting words, and right padding to the second half. If
the string to be padded has odd width the extra padding is applied
on the left.
s:STRING:
Force field splitting at the separator STRING. Note that a STRING
of two or more characters means that all of them must match in
sequence; this differs from the treatment of two or more
characters in the IFS parameter. See also the = flag and the
SH_WORD_SPLIT option.
For historical reasons, the usual behaviour that empty array
elements are retained inside double quotes is disabled for arrays
generated by splitting; hence the following:
line="one::three"
print -l "${(s.:.)line}"
produces two lines of output for one and three and elides the
empty field. To override this behaviour, supply the "(@)" flag as
well, i.e. "${(@s.:.)line}".
The following flags are meaningful with the ${...#...} or ${...%...}
forms. The S and I flags may also be used with the ${.../...} forms.
S
Search substrings as well as beginnings or ends; with # start from
the beginning and with % start from the end of the string. With
substitution via ${.../...} or ${...//...}, specifies non-greedy
matching, i.e. that the shortest instead of the longest match
should be replaced.
I:EXPR:
Search the EXPRth match (where EXPR evaluates to a number). This
only applies when searching for substrings, either with the S
flag, or with ${.../...} (only the EXPRth match is substituted) or
${...//...} (all matches from the EXPRth on are substituted). The
default is to take the first match.
The EXPRth match is counted such that there is either one or zero
matches from each starting position in the string, although for
global substitution matches overlapping previous replacements are
ignored. With the ${...%...} and ${...%%...} forms, the starting
position for the match moves backwards from the end as the index
increases, while with the other forms it moves forward from the
start.
Hence with the string
which switch is the right switch for Ipswich?
substitutions of the form ${(SI:N:)string#w*ch} as N increases
from 1 will match and remove `which', `witch', `witch' and `wich';
the form using `##' will match and remove `which switch is the
right switch for Ipswich', `witch is the right switch for
Ipswich', `witch for Ipswich' and `wich'. The form using `%' will
remove the same matches as for `#', but in reverse order, and the
form using `%%' will remove the same matches as for `##' in reverse
order.
B
Include the index of the beginning of the match in the result.
E
Include the index of the end of the match in the result.
M
Include the matched portion in the result.
N
Include the length of the match in the result.
R
Include the unmatched portion in the result (the _R_est).
14.3.2 Rules
------------
Here is a summary of the rules for substitution; this assumes that
braces are present around the substitution, i.e. ${...}. Some
particular examples are given below. Note that the Zsh Development
Group accepts _no responsibility_ for any brain damage which may occur
during the reading of the following rules.
1. _Nested Substitution_
If multiple nested ${...} forms are present, substitution is
performed from the inside outwards. At each level, the
substitution takes account of whether the current value is a
scalar or an array, whether the whole substitution is in double
quotes, and what flags are supplied to the current level of
substitution, just as if the nested substitution were the
outermost. The flags are not propagated up to enclosing
substitutions; the nested substitution will return either a scalar
or an array as determined by the flags, possibly adjusted for
quoting. All the following steps take place where applicable at
all levels of substitution. Note that, unless the `(P)' flag is
present, the flags and any subscripts apply directly to the value
of the nested substitution; for example, the expansion ${${foo}}
behaves exactly the same as ${foo}.
At each nested level of substitution, the substituted words
undergo all forms of single-word substitution (i.e. not filename
generation), including command substitution, arithmetic expansion
and filename expansion (i.e. leading ~ and =). Thus, for example,
${${:-=cat}:h} expands to the directory where the cat program
resides. (Explanation: the internal substitution has no parameter
but a default value =cat, which is expanded by filename expansion
to a full path; the outer substitution then applies the modifier
:h and takes the directory part of the path.)
2. _Internal Parameter Flags_
Any parameter flags set by one of the typeset family of commands,
in particular the L, R, Z, u and l flags for padding and
capitalization, are applied directly to the parameter value.
3. _Parameter Subscripting_
If the value is a raw parameter reference with a subscript, such as
${VAR[3]}, the effect of subscripting is applied directly to the
parameter. Subscripts are evaluated left to right; subsequent
subscripts apply to the scalar or array value yielded by the
previous subscript. Thus if var is an array, ${var[1][2]} is the
second character of the first word, but ${var[2,4][2]} is the
entire third word (the second word of the range of words two
through four of the original array). Any number of subscripts may
appear.
4. _Parameter Name Replacement_
The effect of any (P) flag, which treats the value so far as a
parameter name and replaces it with the corresponding value, is
applied.
5. _Double-Quoted Joining_
If the value after this process is an array, and the substitution
appears in double quotes, and no (@) flag is present at the current
level, the words of the value are joined with the first character
of the parameter $IFS, by default a space, between each word
(single word arrays are not modified). If the (j) flag is
present, that is used for joining instead of $IFS.
6. _Nested Subscripting_
Any remaining subscripts (i.e. of a nested substitution) are
evaluated at this point, based on whether the value is an array or
a scalar. As with 2., multiple subscripts can appear. Note that
${foo[2,4][2]} is thus equivalent to ${${foo[2,4]}[2]} and also to
"${${(@)foo[2,4]}[2]}" (the nested substitution returns an array in
both cases), but not to "${${foo[2,4]}[2]}" (the nested
substitution returns a scalar because of the quotes).
7. _Modifiers_
Any modifiers, as specified by a trailing `#', `%', `/' (possibly
doubled) or by a set of modifiers of the form :... (see *Note
Modifiers:: in *Note History Expansion::), are applied to the words
of the value at this level.
8. _Forced Joining_
If the `(j)' flag is present, or no `(j)' flag is present but the
string is to be split as given by rules 8. or 9., and joining did
not take place at step 4., any words in the value are joined
together using the given string or the first character of $IFS if
none. Note that the `(F)' flag implicitly supplies a string for
joining in this manner.
9. _Forced Splitting_
If one of the `(s)', `(f)' or `(z)' flags are present, or the `='
specifier was present (e.g. ${=VAR}), the word is split on
occurrences of the specified string, or (for = with neither of the
two flags present) any of the characters in $IFS.
10. _Shell Word Splitting_
If no `(s)', `(f)' or `=' was given, but the word is not quoted
and the option SH_WORD_SPLIT is set, the word is split on
occurrences of any of the characters in $IFS. Note this step, too,
takes place at all levels of a nested substitution.
11. _Uniqueness_
If the result is an array and the `(u)' flag was present, duplicate
elements are removed from the array.
12. _Ordering_
If the result is still an array and one of the `(o)' or `(O)' flags
was present, the array is reordered.
13. _Re-Evaluation_
Any `(e)' flag is applied to the value, forcing it to be
re-examined for new parameter substitutions, but also for command
and arithmetic substitutions.
14. _Padding_
Any padding of the value by the `(l.FILL.)' or `(r.FILL.)' flags
is applied.
15. _Semantic Joining_
In contexts where expansion semantics requires a single word to
result, all words are rejoined with the first character of IFS
between. So in `${(P)${(f)lines}}' the value of ${lines} is split
at newlines, but then must be joined again before the P flag can
be applied.
If a single word is not required, this rule is skipped.
14.3.3 Examples
---------------
The flag f is useful to split a double-quoted substitution line by
line. For example, ${(f)"$(<FILE)"} substitutes the contents of FILE
divided so that each line is an element of the resulting array.
Compare this with the effect of $(<FILE) alone, which divides the file
up by words, or the same inside double quotes, which makes the entire
content of the file a single string.
The following illustrates the rules for nested parameter expansions.
Suppose that $foo contains the array (bar baz):
"${(@)${foo}[1]}"
This produces the result b. First, the inner substitution
"${foo}", which has no array (@) flag, produces a single word
result "bar baz". The outer substitution "${(@)...[1]}" detects
that this is a scalar, so that (despite the `(@)' flag) the
subscript picks the first character.
"${${(@)foo}[1]}"
This produces the result `bar'. In this case, the inner
substitution "${(@)foo}" produces the array `(bar baz)'. The outer
substitution "${...[1]}" detects that this is an array and picks
the first word. This is similar to the simple case "${foo[1]}".
As an example of the rules for word splitting and joining, suppose $foo
contains the array `(ax1 bx1)'. Then
${(s/x/)foo}
produces the words `a', `1 b' and `1'.
${(j/x/s/x/)foo}
produces `a', `1', `b' and `1'.
${(s/x/)foo%%1*}
produces `a' and ` b' (note the extra space). As substitution
occurs before either joining or splitting, the operation first
generates the modified array (ax bx), which is joined to give "ax
bx", and then split to give `a', ` b' and `'. The final empty
string will then be elided, as it is not in double quotes.
File: zsh.info, Node: Command Substitution, Next: Arithmetic Expansion, Prev: Parameter Expansion, Up: Expansion
14.4 Command Substitution
=========================
A command enclosed in parentheses preceded by a dollar sign, like
`$(...)', or quoted with grave accents, like ``...`', is replaced with
its standard output, with any trailing newlines deleted. If the
substitution is not enclosed in double quotes, the output is broken
into words using the IFS parameter. The substitution `$(cat FOO)' may
be replaced by the equivalent but faster `$(<FOO)'. In either case, if
the option GLOB_SUBST is set, the output is eligible for filename
generation.
File: zsh.info, Node: Arithmetic Expansion, Next: Brace Expansion, Prev: Command Substitution, Up: Expansion
14.5 Arithmetic Expansion
=========================
A string of the form `$[EXP]' or `$((EXP))' is substituted with the
value of the arithmetic expression EXP. EXP is subjected to _parameter
expansion_, _command substitution_ and _arithmetic expansion_ before it
is evaluated. See *Note Arithmetic Evaluation::.
File: zsh.info, Node: Brace Expansion, Next: Filename Expansion, Prev: Arithmetic Expansion, Up: Expansion
14.6 Brace Expansion
====================
A string of the form `FOO{XX,YY,ZZ}BAR' is expanded to the individual
words `FOOXXBAR', `FOOYYBAR' and `FOOZZBAR'. Left-to-right order is
preserved. This construct may be nested. Commas may be quoted in
order to include them literally in a word.
An expression of the form `{N1..N2}', where N1 and N2 are integers, is
expanded to every number between N1 and N2 inclusive. If either number
begins with a zero, all the resulting numbers will be padded with
leading zeroes to that minimum width. If the numbers are in decreasing
order the resulting sequence will also be in decreasing order.
If a brace expression matches none of the above forms, it is left
unchanged, unless the option BRACE_CCL (an abbreviation for `brace
character class') is set. In that case, it is expanded to a list of
the individual characters between the braces sorted into the order of
the characters in the ASCII character set (multibyte characters are not
currently handled). The syntax is similar to a [...] expression in
filename generation: `-' is treated specially to denote a range of
characters, but `^' or `!' as the first character is treated normally.
For example, `{abcdef0-9}' expands to 16 words 0 1 2 3 4 5 6 7 8 9 a b
c d e f.
Note that brace expansion is not part of filename generation
(globbing); an expression such as */{foo,bar} is split into two
separate words */foo and */bar before filename generation takes place.
In particular, note that this is liable to produce a `no match' error if
_either_ of the two expressions does not match; this is to be contrasted
with */(foo|bar), which is treated as a single pattern but otherwise
has similar effects.
To combine brace expansion with array expansion, see the ${^SPEC} form
described in *Note Parameter Expansion:: above.
File: zsh.info, Node: Filename Expansion, Next: Filename Generation, Prev: Brace Expansion, Up: Expansion
14.7 Filename Expansion
=======================
Each word is checked to see if it begins with an unquoted `~'. If it
does, then the word up to a `/', or the end of the word if there is no
`/', is checked to see if it can be substituted in one of the ways
described here. If so, then the `~' and the checked portion are
replaced with the appropriate substitute value.
A `~' by itself is replaced by the value of $HOME. A `~' followed by a
`+' or a `-' is replaced by the value of $PWD or $OLDPWD, respectively.
A `~' followed by a number is replaced by the directory at that
position in the directory stack. `~0' is equivalent to `~+', and `~1'
is the top of the stack. `~+' followed by a number is replaced by the
directory at that position in the directory stack. `~+0' is equivalent
to `~+', and `~+1' is the top of the stack. `~-' followed by a number
is replaced by the directory that many positions from the bottom of the
stack. `~-0' is the bottom of the stack. The PUSHD_MINUS option
exchanges the effects of `~+' and `~-' where they are followed by a
number.
14.7.1 Dynamic named directories
--------------------------------
The feature described here is only available if the shell function
zsh_directory_name exists.
A `~' followed by a string NAMSTR in unquoted square brackets is
treated specially as a dynamic directory name. Note that the first
unquoted closing square bracket always terminates NAMSTR. The shell
function is passed two arguments: the string n (for name) and NAMSTR.
It should either set the array reply to a single element which is the
directory corresponding to the name and return status zero (executing
an assignment as the last statement is usually sufficient), or it
should return status non-zero. In the former case the element of reply
is used as the directory; in the latter case the substitution is deemed
to have failed and NOMATCH handling is applied if the option is set.
The function zsh_directory_name is also used to see if a directory can
be turned into a name, for example when printing the directory stack or
when expanding %~ in prompts. In this case the function is passed two
arguments: the string d (for directory) and the candidate for dynamic
naming. The function should either return non-zero status, if the
directory cannot be named by the function, or it should set the array
reply to consist of two elements: the first is the dynamic name for the
directory (as would appear within `~[...]'), and the second is the
prefix length of the directory to be replaced. For example, if the
trial directory is /home/myname/src/zsh and the dynamic name for
/home/myname/src (which has 16 characters) is s, then the function sets
reply=(s 16)
The directory name so returned is compared with possible static names
for parts of the directory path, as described below; it is used if the
prefix length matched (16 in the example) is longer than that matched
by any static name.
As a working example, here is a function that expands any dynamic names
beginning with the string p: to directories below /home/pws/perforce.
In this simple case a static name for the directory would be just as
effective.
zsh_directory_name() {
emulate -L zsh
setopt extendedglob
local -a match mbegin mend
if [[ $1 = d ]]; then
if [[ $2 = (#b)(/home/pws/perforce/)([^/]##)* ]]; then
typeset -ga reply
reply=(p:$match[2] $(( ${#match[1]} + ${#match[2]} )) )
else
return 1
fi
else
[[ $2 != (#b)p:(?*) ]] && return 1
typeset -ga reply
reply=(/home/pws/perforce/$match[1])
fi
return 0
}
14.7.2 Static named directories
-------------------------------
A `~' followed by anything not already covered consisting of any number
of alphanumeric characters or underscore (`_'), hyphen (`-'), or dot
(`.') is looked up as a named directory, and replaced by the value of
that named directory if found. Named directories are typically home
directories for users on the system. They may also be defined if the
text after the `~' is the name of a string shell parameter whose value
begins with a `/'. Note that trailing slashes will be removed from the
path to the directory (though the original parameter is not modified).
It is also possible to define directory names using the -d option to the
hash builtin.
In certain circumstances (in prompts, for instance), when the shell
prints a path, the path is checked to see if it has a named directory
as its prefix. If so, then the prefix portion is replaced with a `~'
followed by the name of the directory. The shortest way of referring
to the directory is used, with ties broken in favour of using a named
directory, except when the directory is / itself. The parameters $PWD
and $OLDPWD are never abbreviated in this fashion.
14.7.3 `=' expansion
--------------------
If a word begins with an unquoted `=' and the EQUALS option is set, the
remainder of the word is taken as the name of a command. If a command
exists by that name, the word is replaced by the full pathname of the
command.
14.7.4 Notes
------------
Filename expansion is performed on the right hand side of a parameter
assignment, including those appearing after commands of the typeset
family. In this case, the right hand side will be treated as a
colon-separated list in the manner of the PATH parameter, so that a `~'
or an `=' following a `:' is eligible for expansion. All such
behaviour can be disabled by quoting the `~', the `=', or the whole
expression (but not simply the colon); the EQUALS option is also
respected.
If the option MAGIC_EQUAL_SUBST is set, any unquoted shell argument in
the form `IDENTIFIER=EXPRESSION' becomes eligible for file expansion as
described in the previous paragraph. Quoting the first `=' also
inhibits this.
File: zsh.info, Node: Filename Generation, Prev: Filename Expansion, Up: Expansion
14.8 Filename Generation
========================
If a word contains an unquoted instance of one of the characters `*',
`(', `|', `<', `[', or `?', it is regarded as a pattern for filename
generation, unless the GLOB option is unset. If the EXTENDED_GLOB
option is set, the `^' and `#' characters also denote a pattern;
otherwise they are not treated specially by the shell.
The word is replaced with a list of sorted filenames that match the
pattern. If no matching pattern is found, the shell gives an error
message, unless the NULL_GLOB option is set, in which case the word is
deleted; or unless the NOMATCH option is unset, in which case the word
is left unchanged.
In filename generation, the character `/' must be matched explicitly;
also, a `.' must be matched explicitly at the beginning of a pattern or
after a `/', unless the GLOB_DOTS option is set. No filename
generation pattern matches the files `.' or `..'. In other instances
of pattern matching, the `/' and `.' are not treated specially.
14.8.1 Glob Operators
---------------------
*
Matches any string, including the null string.
?
Matches any character.
[...]
Matches any of the enclosed characters. Ranges of characters can
be specified by separating two characters by a `-'. A `-' or `]'
may be matched by including it as the first character in the list. There
are also several named classes of characters, in the form
`[:NAME:]' with the following meanings. The first set use the
macros provided by the operating system to test for the given
character combinations, including any modifications due to local
language settings, see man page ctype(3):
[:alnum:]
The character is alphanumeric
[:alpha:]
The character is alphabetic
[:ascii:]
The character is 7-bit, i.e. is a single-byte character
without the top bit set.
[:blank:]
The character is either space or tab
[:cntrl:]
The character is a control character
[:digit:]
The character is a decimal digit
[:graph:]
The character is a printable character other than whitespace
[:lower:]
The character is a lowercase letter
[:print:]
The character is printable
[:punct:]
The character is printable but neither alphanumeric nor
whitespace
[:space:]
The character is whitespace
[:upper:]
The character is an uppercase letter
[:xdigit:]
The character is a hexadecimal digit
Another set of named classes is handled internally by the shell and
is not sensitive to the locale:
[:IDENT:]
The character is allowed to form part of a shell identifier,
such as a parameter name
[:IFS:]
The character is used as an input field separator, i.e. is
contained in the IFS parameter
[:IFSSPACE:]
The character is an IFS white space character; see the
documentation for IFS in *Note Parameters Used By The Shell::.
[:WORD:]
The character is treated as part of a word; this test is
sensitive to the value of the WORDCHARS parameter
Note that the square brackets are additional to those enclosing
the whole set of characters, so to test for a single alphanumeric
character you need `[[:alnum:]]'. Named character sets can be
used alongside other types, e.g. `[[:alpha:]0-9]'.
[^...]
[!...]
Like [...], except that it matches any character which is not in
the given set.
<[X]-[Y]>
Matches any number in the range X to Y, inclusive. Either of the
numbers may be omitted to make the range open-ended; hence `<->'
matches any number. To match individual digits, the [...] form is
more efficient.
Be careful when using other wildcards adjacent to patterns of this
form; for example, <0-9>* will actually match any number
whatsoever at the start of the string, since the `<0-9>' will
match the first digit, and the `*' will match any others. This is
a trap for the unwary, but is in fact an inevitable consequence of
the rule that the longest possible match always succeeds.
Expressions such as `<0-9>[^[:digit:]]*' can be used instead.
(...)
Matches the enclosed pattern. This is used for grouping. If the
KSH_GLOB option is set, then a `@', `*', `+', `?' or `!'
immediately preceding the `(' is treated specially, as detailed
below. The option SH_GLOB prevents bare parentheses from being
used in this way, though the KSH_GLOB option is still available.
Note that grouping cannot extend over multiple directories: it is
an error to have a `/' within a group (this only applies for
patterns used in filename generation). There is one exception: a
group of the form (PAT/)# appearing as a complete path segment can
match a sequence of directories. For example, foo/(a*/)#bar
matches foo/bar, foo/any/bar, foo/any/anyother/bar, and so on.
X|Y
Matches either X or Y. This operator has lower precedence than
any other. The `|' character must be within parentheses, to avoid
interpretation as a pipeline.
^X
(Requires EXTENDED_GLOB to be set.) Matches anything except the
pattern X. This has a higher precedence than `/', so `^foo/bar'
will search directories in `.' except `./foo' for a file named
`bar'.
X~Y
(Requires EXTENDED_GLOB to be set.) Match anything that matches
the pattern X but does not match Y. This has lower precedence
than any operator except `|', so `*/*~foo/bar' will search for all
files in all directories in `.' and then exclude `foo/bar' if
there was such a match. Multiple patterns can be excluded by
`FOO~BAR~BAZ'. In the exclusion pattern (Y), `/' and `.' are not
treated specially the way they usually are in globbing.
X#
(Requires EXTENDED_GLOB to be set.) Matches zero or more
occurrences of the pattern X. This operator has high precedence;
`12#' is equivalent to `1(2#)', rather than `(12)#'. It is an
error for an unquoted `#' to follow something which cannot be
repeated; this includes an empty string, a pattern already
followed by `##', or parentheses when part of a KSH_GLOB pattern
(for example, `!(FOO)#' is invalid and must be replaced by
`*(!(FOO))').
X##
(Requires EXTENDED_GLOB to be set.) Matches one or more
occurrences of the pattern X. This operator has high precedence;
`12##' is equivalent to `1(2##)', rather than `(12)##'. No more
than two active `#' characters may appear together. (Note the
potential clash with glob qualifiers in the form `1(2##)' which
should therefore be avoided.)
14.8.2 ksh-like Glob Operators
------------------------------
If the KSH_GLOB option is set, the effects of parentheses can be
modified by a preceding `@', `*', `+', `?' or `!'. This character need
not be unquoted to have special effects, but the `(' must be.
@(...)
Match the pattern in the parentheses. (Like `(...)'.)
*(...)
Match any number of occurrences. (Like `(...)#'.)
+(...)
Match at least one occurrence. (Like `(...)##'.)
?(...)
Match zero or one occurrence. (Like `(|...)'.)
!(...)
Match anything but the expression in parentheses. (Like
`(^(...))'.)
14.8.3 Precedence
-----------------
The precedence of the operators given above is (highest) `^', `/', `~',
`|' (lowest); the remaining operators are simply treated from left to
right as part of a string, with `#' and `##' applying to the shortest
possible preceding unit (i.e. a character, `?', `[...]', `<...>', or a
parenthesised expression). As mentioned above, a `/' used as a
directory separator may not appear inside parentheses, while a `|' must
do so; in patterns used in other contexts than filename generation (for
example, in case statements and tests within `[[...]]'), a `/' is not
special; and `/' is also not special after a `~' appearing outside
parentheses in a filename pattern.
14.8.4 Globbing Flags
---------------------
There are various flags which affect any text to their right up to the
end of the enclosing group or to the end of the pattern; they require
the EXTENDED_GLOB option. All take the form (#X) where X may have one
of the following forms:
i
Case insensitive: upper or lower case characters in the pattern
match upper or lower case characters.
l
Lower case characters in the pattern match upper or lower case
characters; upper case characters in the pattern still only match
upper case characters.
I
Case sensitive: locally negates the effect of i or l from that
point on.
b
Activate backreferences for parenthesised groups in the pattern;
this does not work in filename generation. When a pattern with a
set of active parentheses is matched, the strings matched by the
groups are stored in the array $match, the indices of the
beginning of the matched parentheses in the array $mbegin, and the
indices of the end in the array $mend, with the first element of
each array corresponding to the first parenthesised group, and so
on. These arrays are not otherwise special to the shell. The
indices use the same convention as does parameter substitution, so
that elements of $mend and $mbegin may be used in subscripts; the
KSH_ARRAYS option is respected. Sets of globbing flags are not
considered parenthesised groups; only the first nine active
parentheses can be referenced.
For example,
foo="a string with a message"
if [[ $foo = (a|an)' '(#b)(*)' '* ]]; then
print ${foo[$mbegin[1],$mend[1]]}
fi
prints `string with a'. Note that the first parenthesis is before
the (#b) and does not create a backreference.
Backreferences work with all forms of pattern matching other than
filename generation, but note that when performing matches on an
entire array, such as ${ARRAY#PATTERN}, or a global substitution,
such as ${PARAM//PAT/REPL}, only the data for the last match
remains available. In the case of global replacements this may
still be useful. See the example for the m flag below.
The numbering of backreferences strictly follows the order of the
opening parentheses from left to right in the pattern string,
although sets of parentheses may be nested. There are special
rules for parentheses followed by `#' or `##'. Only the last
match of the parenthesis is remembered: for example, in `[[ abab =
(#b)([ab])# ]]', only the final `b' is stored in match[1]. Thus
extra parentheses may be necessary to match the complete segment:
for example, use `X((ab|cd)#)Y' to match a whole string of either
`ab' or `cd' between `X' and `Y', using the value of $match[1]
rather than $match[2].
If the match fails none of the parameters is altered, so in some
cases it may be necessary to initialise them beforehand. If some
of the backreferences fail to match -- which happens if they are
in an alternate branch which fails to match, or if they are
followed by # and matched zero times -- then the matched string is
set to the empty string, and the start and end indices are set to
-1.
Pattern matching with backreferences is slightly slower than
without.
B
Deactivate backreferences, negating the effect of the b flag from
that point on.
cN,M
The flag (#cN,M) can be used anywhere that the # or ## operators
can be used; it cannot be combined with other globbing flags and a
bad pattern error occurs if it is misplaced. It is equivalent to
the form {N,M} in regular expressions. The previous character or
group is required to match between N and M times, inclusive. The
form (#cN) requires exactly N matches; (#c,M) is equivalent to
specifying N as 0; (#cN,) specifies that there is no maximum limit
on the number of matches.
m
Set references to the match data for the entire string matched;
this is similar to backreferencing and does not work in filename
generation. The flag must be in effect at the end of the pattern,
i.e. not local to a group. The parameters $MATCH, $MBEGIN and
$MEND will be set to the string matched and to the indices of the
beginning and end of the string, respectively. This is most
useful in parameter substitutions, as otherwise the string matched
is obvious.
For example,
arr=(veldt jynx grimps waqf zho buck)
print ${arr//(#m)[aeiou]/${(U)MATCH}}
forces all the matches (i.e. all vowels) into uppercase, printing
`vEldt jynx grImps wAqf zhO bUck'.
Unlike backreferences, there is no speed penalty for using match
references, other than the extra substitutions required for the
replacement strings in cases such as the example shown.
M
Deactivate the m flag, hence no references to match data will be
created.
aNUM
Approximate matching: NUM errors are allowed in the string matched
by the pattern. The rules for this are described in the next
subsection.
s, e
Unlike the other flags, these have only a local effect, and each
must appear on its own: `(#s)' and `(#e)' are the only valid
forms. The `(#s)' flag succeeds only at the start of the test
string, and the `(#e)' flag succeeds only at the end of the test
string; they correspond to `^' and `$' in standard regular
expressions. They are useful for matching path segments in
patterns other than those in filename generation (where path
segments are in any case treated separately). For example,
`*((#s)|/)test((#e)|/)*' matches a path segment `test' in any of
the following strings: test, test/at/start, at/end/test,
in/test/middle.
Another use is in parameter substitution; for example
`${array/(#s)A*Z(#e)}' will remove only elements of an array which
match the complete pattern `A*Z'. There are other ways of
performing many operations of this type, however the combination
of the substitution operations `/' and `//' with the `(#s)' and
`(#e)' flags provides a single simple and memorable method.
Note that assertions of the form `(^(#s))' also work, i.e. match
anywhere except at the start of the string, although this actually
means `anything except a zero-length portion at the start of the
string'; you need to use `(""~(#s))' to match a zero-length
portion of the string not at the start.
q
A `q' and everything up to the closing parenthesis of the globbing
flags are ignored by the pattern matching code. This is intended
to support the use of glob qualifiers, see below. The result is
that the pattern `(#b)(*).c(#q.)' can be used both for globbing
and for matching against a string. In the former case, the
`(#q.)' will be treated as a glob qualifier and the `(#b)' will
not be useful, while in the latter case the `(#b)' is useful for
backreferences and the `(#q.)' will be ignored. Note that colon
modifiers in the glob qualifiers are also not applied in ordinary
pattern matching.
u
Respect the current locale in determining the presence of multibyte
characters in a pattern, provided the shell was compiled with
MULTIBYTE_SUPPORT. This overrides the MULTIBYTE option; the
default behaviour is taken from the option. Compare U.
(Mnemonic: typically multibyte characters are from Unicode in the
UTF-8 encoding, although any extension of ASCII supported by the
system library may be used.)
U
All characters are considered to be a single byte long. The
opposite of u. This overrides the MULTIBYTE option.
For example, the test string fooxx can be matched by the pattern
(#i)FOOXX, but not by (#l)FOOXX, (#i)FOO(#I)XX or ((#i)FOOX)X. The
string (#ia2)readme specifies case-insensitive matching of readme with
up to two errors.
When using the ksh syntax for grouping both KSH_GLOB and EXTENDED_GLOB
must be set and the left parenthesis should be preceded by @. Note
also that the flags do not affect letters inside [...] groups, in other
words (#i)[a-z] still matches only lowercase letters. Finally, note
that when examining whole paths case-insensitively every directory must
be searched for all files which match, so that a pattern of the form
(#i)/foo/bar/... is potentially slow.
14.8.5 Approximate Matching
---------------------------
When matching approximately, the shell keeps a count of the errors
found, which cannot exceed the number specified in the (#aNUM) flags.
Four types of error are recognised:
1.
Different characters, as in fooxbar and fooybar.
2.
Transposition of characters, as in banana and abnana.
3.
A character missing in the target string, as with the pattern road
and target string rod.
4.
An extra character appearing in the target string, as with stove
and strove.
Thus, the pattern (#a3)abcd matches dcba, with the errors occurring by
using the first rule twice and the second once, grouping the string as
[d][cb][a] and [a][bc][d].
Non-literal parts of the pattern must match exactly, including
characters in character ranges: hence (#a1)??? matches strings of
length four, by applying rule 4 to an empty part of the pattern, but not
strings of length two, since all the ? must match. Other characters
which must match exactly are initial dots in filenames (unless the
GLOB_DOTS option is set), and all slashes in filenames, so that a/bc is
two errors from ab/c (the slash cannot be transposed with another
character). Similarly, errors are counted separately for
non-contiguous strings in the pattern, so that (ab|cd)ef is two errors
from aebf.
When using exclusion via the ~ operator, approximate matching is
treated entirely separately for the excluded part and must be activated
separately. Thus, (#a1)README~READ_ME matches READ.ME but not READ_ME,
as the trailing READ_ME is matched without approximation. However,
(#a1)README~(#a1)READ_ME does not match any pattern of the form READ?ME
as all such forms are now excluded.
Apart from exclusions, there is only one overall error count; however,
the maximum errors allowed may be altered locally, and this can be
delimited by grouping. For example, (#a1)cat((#a0)dog)fox allows one
error in total, which may not occur in the dog section, and the pattern
(#a1)cat(#a0)dog(#a1)fox is equivalent. Note that the point at which
an error is first found is the crucial one for establishing whether to
use approximation; for example, (#a1)abc(#a0)xyz will not match
abcdxyz, because the error occurs at the `x', where approximation is
turned off.
Entire path segments may be matched approximately, so that
`(#a1)/foo/d/is/available/at/the/bar' allows one error in any path
segment. This is much less efficient than without the (#a1), however,
since every directory in the path must be scanned for a possible
approximate match. It is best to place the (#a1) after any path
segments which are known to be correct.
14.8.6 Recursive Globbing
-------------------------
A pathname component of the form `(FOO/)#' matches a path consisting of
zero or more directories matching the pattern FOO.
As a shorthand, `**/' is equivalent to `(*/)#'; note that this
therefore matches files in the current directory as well as
subdirectories. Thus:
ls (*/)#bar
or
ls **/bar
does a recursive directory search for files named `bar' (potentially
including the file `bar' in the current directory). This form does not
follow symbolic links; the alternative form `***/' does, but is
otherwise identical. Neither of these can be combined with other forms
of globbing within the same path segment; in that case, the `*'
operators revert to their usual effect.
14.8.7 Glob Qualifiers
----------------------
Patterns used for filename generation may end in a list of qualifiers
enclosed in parentheses. The qualifiers specify which filenames that
otherwise match the given pattern will be inserted in the argument list.
If the option BARE_GLOB_QUAL is set, then a trailing set of parentheses
containing no `|' or `(' characters (or `~' if it is special) is taken
as a set of glob qualifiers. A glob subexpression that would normally
be taken as glob qualifiers, for example `(^x)', can be forced to be
treated as part of the glob pattern by doubling the parentheses, in
this case producing `((^x))'.
If the option EXTENDED_GLOB is set, a different syntax for glob
qualifiers is available, namely `(#qx)' where x is any of the same glob
qualifiers used in the other format. The qualifiers must still appear
at the end of the pattern. However, with this syntax multiple glob
qualifiers may be chained together. They are treated as a logical AND
of the individual sets of flags. Also, as the syntax is unambiguous,
the expression will be treated as glob qualifiers just as long any
parentheses contained within it are balanced; appearance of `|', `(' or
`~' does not negate the effect. Note that qualifiers will be
recognised in this form even if a bare glob qualifier exists at the end
of the pattern, for example `*(#q*)(.)' will recognise executable
regular files if both options are set; however, mixed syntax should
probably be avoided for the sake of clarity.
A qualifier may be any one of the following:
/
directories
F
`full' (i.e. non-empty) directories. Note that the opposite sense
(^F) expands to empty directories and all non-directories. Use
(/^F) for empty directories
.
plain files
@
symbolic links
=
sockets
p
named pipes (FIFOs)
*
executable plain files (0100)
%
device files (character or block special)
%b
block special files
%c
character special files
r
owner-readable files (0400)
w
owner-writable files (0200)
x
owner-executable files (0100)
A
group-readable files (0040)
I
group-writable files (0020)
E
group-executable files (0010)
R
world-readable files (0004)
W
world-writable files (0002)
X
world-executable files (0001)
s
setuid files (04000)
S
setgid files (02000)
t
files with the sticky bit (01000)
fSPEC
files with access rights matching SPEC. This SPEC may be a octal
number optionally preceded by a `=', a `+', or a `-'. If none of
these characters is given, the behavior is the same as for `='.
The octal number describes the mode bits to be expected, if
combined with a `=', the value given must match the file-modes
exactly, with a `+', at least the bits in the given number must be
set in the file-modes, and with a `-', the bits in the number must
not be set. Giving a `?' instead of a octal digit anywhere in the
number ensures that the corresponding bits in the file-modes are
not checked, this is only useful in combination with `='.
If the qualifier `f' is followed by any other character anything
up to the next matching character (`[', `{', and `<' match `]',
`}', and `>' respectively, any other character matches itself) is
taken as a list of comma-separated SUB-SPECs. Each SUB-SPEC may be
either an octal number as described above or a list of any of the
characters `u', `g', `o', and `a', followed by a `=', a `+', or a
`-', followed by a list of any of the characters `r', `w', `x',
`s', and `t', or an octal digit. The first list of characters
specify which access rights are to be checked. If a `u' is given,
those for the owner of the file are used, if a `g' is given, those
of the group are checked, a `o' means to test those of other
users, and the `a' says to test all three groups. The `=', `+',
and `-' again says how the modes are to be checked and have the
same meaning as described for the first form above. The second
list of characters finally says which access rights are to be
expected: `r' for read access, `w' for write access, `x' for the
right to execute the file (or to search a directory), `s' for the
setuid and setgid bits, and `t' for the sticky bit.
Thus, `*(f70?)' gives the files for which the owner has read,
write, and execute permission, and for which other group members
have no rights, independent of the permissions for other users.
The pattern `*(f-100)' gives all files for which the owner does
not have execute permission, and `*(f:gu+w,o-rx:)' gives the files
for which the owner and the other members of the group have at
least write permission, and for which other users don't have read
or execute permission.
eSTRING
+CMD
The STRING will be executed as shell code. The filename will be
included in the list if and only if the code returns a zero status
(usually the status of the last command). The first character
after the `e' will be used as a separator and anything up to the
next matching separator will be taken as the STRING; `[', `{',
and `<' match `]', `}', and `>', respectively, while any other
character matches itself. Note that expansions must be quoted in
the STRING to prevent them from being expanded before globbing is
done.
During the execution of STRING the filename currently being tested
is available in the parameter REPLY; the parameter may be altered
to a string to be inserted into the list instead of the original
filename. In addition, the parameter reply may be set to an array
or a string, which overrides the value of REPLY. If set to an
array, the latter is inserted into the command line word by word.
For example, suppose a directory contains a single file `lonely'.
Then the expression `*(e:'reply=(${REPLY}{1,2})':)' will cause the
words `lonely1 lonely2' to be inserted into the command line.
Note the quotation marks.
The form +CMD has the same effect, but no delimiters appear around
CMD. Instead, CMD is taken as the longest sequence of characters
following the + that are alphanumeric or underscore. Typically
CMD will be the name of a shell function that contains the
appropriate test. For example,
nt() { [[ $REPLY -nt $NTREF ]] }
NTREF=reffile
ls -l *(+nt)
lists all files in the directory that have been modified more
recently than reffile.
dDEV
files on the device DEV
l[-|+]CT
files having a link count less than CT (-), greater than CT (+),
or equal to CT
U
files owned by the effective user ID
G
files owned by the effective group ID
uID
files owned by user ID ID if that is a number. Otherwise, ID
specifies a user name: the character after the `u' will be taken
as a separator and the string between it and the next matching
separator will be taken as a user name. The starting separators
`[', `{', and `<' match the final separators `]', `}', and `>',
respectively; any other character matches itself. The selected
files are those owned by this user. For example, `u:foo:' or
`u[foo]' selects files owned by user `foo'.
gID
like uID but with group IDs or names
a[Mwhms][-|+]N
files accessed exactly N days ago. Files accessed within the last
N days are selected using a negative value for N (-N). Files
accessed more than N days ago are selected by a positive N value
(+N). Optional unit specifiers `M', `w', `h', `m' or `s' (e.g.
`ah5') cause the check to be performed with months (of 30 days),
weeks, hours, minutes or seconds instead of days, respectively.
Any fractional part of the difference between the access time and
the current part in the appropriate units is ignored in the
comparison. For instance, `echo *(ah-5)' would echo files
accessed within the last five hours, while `echo *(ah+5)' would
echo files accessed at least six hours ago, as times strictly
between five and six hours are treated as five hours.
m[Mwhms][-|+]N
like the file access qualifier, except that it uses the file
modification time.
c[Mwhms][-|+]N
like the file access qualifier, except that it uses the file inode
change time.
L[+|-]N
files less than N bytes (-), more than N bytes (+), or exactly N
bytes in length. If this flag is directly followed by a `k' (`K'),
`m' (`M'), or `p' (`P') (e.g. `Lk-50') the check is performed with
kilobytes, megabytes, or blocks (of 512 bytes) instead.
^
negates all qualifiers following it
-
toggles between making the qualifiers work on symbolic links (the
default) and the files they point to
M
sets the MARK_DIRS option for the current pattern
T
appends a trailing qualifier mark to the filenames, analogous to
the LIST_TYPES option, for the current pattern (overrides M)
N
sets the NULL_GLOB option for the current pattern
D
sets the GLOB_DOTS option for the current pattern
n
sets the NUMERIC_GLOB_SORT option for the current pattern
oC
specifies how the names of the files should be sorted. If C is n
they are sorted by name (the default); if it is L they are sorted
depending on the size (length) of the files; if l they are sorted
by the number of links; if a, m, or c they are sorted by the time
of the last access, modification, or inode change respectively; if
d, files in subdirectories appear before those in the current
directory at each level of the search -- this is best combined
with other criteria, for example `odon' to sort on names for files
within the same directory; if N, no sorting is performed. Note
that a, m, and c compare the age against the current time, hence
the first name in the list is the youngest file. Also note that
the modifiers ^ and - are used, so `*(^-oL)' gives a list of all
files sorted by file size in descending order, following any
symbolic links. Unless oN is used, multiple order specifiers may
occur to resolve ties.
oe and o+ are special cases; they are each followed by shell code,
delimited as for the e glob qualifier and the + glob qualifier
respectively (see above). The code is executed for each matched
file with the parameter REPLY set to the name of the file on
entry. The code should modify the parameter REPLY in some
fashion. On return, the value of the parameter is used instead of
the file name as the string on which to sort. Unlike other sort
operators, oe and o+ may be repeated, but note that the maximum
number of sort operators of any kind that may appear in any glob
expression is 12.
OC
like `o', but sorts in descending order; i.e. `*(^oc)' is the same
as `*(Oc)' and `*(^Oc)' is the same as `*(oc)'; `Od' puts files in
the current directory before those in subdirectories at each level
of the search.
[BEG[,END]]
specifies which of the matched filenames should be included in the
returned list. The syntax is the same as for array subscripts. BEG
and the optional END may be mathematical expressions. As in
parameter subscripting they may be negative to make them count
from the last match backward. E.g.: `*(-OL[1,3])' gives a list of
the names of the three largest files.
More than one of these lists can be combined, separated by commas. The
whole list matches if at least one of the sublists matches (they are
`or'ed, the qualifiers in the sublists are `and'ed). Some qualifiers,
however, affect all matches generated, independent of the sublist in
which they are given. These are the qualifiers `M', `T', `N', `D',
`n', `o', `O' and the subscripts given in brackets (`[...]').
If a `:' appears in a qualifier list, the remainder of the expression in
parenthesis is interpreted as a modifier (see *Note Modifiers:: in
*Note History Expansion::). Each modifier must be introduced by a
separate `:'. Note also that the result after modification does not
have to be an existing file. The name of any existing file can be
followed by a modifier of the form `(:..)' even if no actual filename
generation is performed, although note that the presence of the
parentheses causes the entire expression to be subjected to any global
pattern matching options such as NULL_GLOB. Thus:
ls *(-/)
lists all directories and symbolic links that point to directories, and
ls *(%W)
lists all world-writable device files in the current directory, and
ls *(W,X)
lists all files in the current directory that are world-writable or
world-executable, and
echo /tmp/foo*(u0^@:t)
outputs the basename of all root-owned files beginning with the string
`foo' in /tmp, ignoring symlinks, and
ls *.*~(lex|parse).[ch](^D^l1)
lists all files having a link count of one whose names contain a dot
(but not those starting with a dot, since GLOB_DOTS is explicitly
switched off) except for lex.c, lex.h, parse.c and parse.h.
print b*.pro(#q:s/pro/shmo/)(#q.:s/builtin/shmiltin/)
demonstrates how colon modifiers and other qualifiers may be chained
together. The ordinary qualifier `.' is applied first, then the colon
modifiers in order from left to right. So if EXTENDED_GLOB is set and
the base pattern matches the regular file builtin.pro, the shell will
print `shmiltin.shmo'.
File: zsh.info, Node: Parameters, Next: Options, Prev: Expansion, Up: Top
15 Parameters
*************
15.1 Description
================
A parameter has a name, a value, and a number of attributes. A name
may be any sequence of alphanumeric characters and underscores, or the
single characters `*', `@', `#', `?', `-', `$', or `!'. The value may
be a _scalar_ (a string), an integer, an array (indexed numerically),
or an _associative_ array (an unordered set of name-value pairs,
indexed by name). To declare the type of a parameter, or to assign a
scalar or integer value to a parameter, use the typeset builtin.
The value of a scalar or integer parameter may also be assigned by
writing:
NAME=VALUE
If the integer attribute, -i, is set for NAME, the VALUE is subject to
arithmetic evaluation. Furthermore, by replacing `=' with `+=', a
parameter can be added or appended to. See *Note Array Parameters::
for additional forms of assignment.
To refer to the value of a parameter, write `$NAME' or `${NAME}'. See
*Note Parameter Expansion:: for complete details.
In the parameter lists that follow, the mark `<S>' indicates that the
parameter is special. Special parameters cannot have their type
changed or their readonly attribute turned off, and if a special
parameter is unset, then later recreated, the special properties will
be retained. `<Z>' indicates that the parameter does not exist when
the shell initializes in sh or ksh emulation mode.
* Menu:
* Array Parameters::
* Positional Parameters::
* Local Parameters::
* Parameters Set By The Shell::
* Parameters Used By The Shell::
File: zsh.info, Node: Array Parameters, Next: Positional Parameters, Up: Parameters
15.2 Array Parameters
=====================
To assign an array value, write one of:
set -A NAME VALUE ...
NAME=(VALUE ...)
If no parameter NAME exists, an ordinary array parameter is created.
If the parameter NAME exists and is a scalar, it is replaced by a new
array. Ordinary array parameters may also be explicitly declared with:
typeset -a NAME
Associative arrays _must_ be declared before assignment, by using:
typeset -A NAME
When NAME refers to an associative array, the list in an assignment is
interpreted as alternating keys and values:
set -A NAME KEY VALUE ...
NAME=(KEY VALUE ...)
Every KEY must have a VALUE in this case. Note that this assigns to
the entire array, deleting any elements that do not appear in the list.
To create an empty array (including associative arrays), use one of:
set -A NAME
NAME=()
15.2.1 Array Subscripts
-----------------------
Individual elements of an array may be selected using a subscript. A
subscript of the form `[EXP]' selects the single element EXP, where EXP
is an arithmetic expression which will be subject to arithmetic
expansion as if it were surrounded by `$((...))'. The elements are
numbered beginning with 1, unless the KSH_ARRAYS option is set in which
case they are numbered from zero.
Subscripts may be used inside braces used to delimit a parameter name,
thus `${foo[2]}' is equivalent to `$foo[2]'. If the KSH_ARRAYS option
is set, the braced form is the only one that works, as bracketed
expressions otherwise are not treated as subscripts.
If the KSH_ARRAYS option is not set, then by default accesses to an
array element with a subscript that evaluates to zero return an empty
string, while an attempt to write such an element is treated as an
error. For backward compatibility the KSH_ZERO_SUBSCRIPT option can be
set to cause subscript values 0 and 1 to be equivalent; see the
description of the option in *Note Description of Options::.
The same subscripting syntax is used for associative arrays, except that
no arithmetic expansion is applied to EXP. However, the parsing rules
for arithmetic expressions still apply, which affects the way that
certain special characters must be protected from interpretation. See
_Subscript Parsing_ below for details.
A subscript of the form `[*]' or `[@]' evaluates to all elements of an
array; there is no difference between the two except when they appear
within double quotes. `"$foo[*]"' evaluates to `"$foo[1] $foo[2]
..."', whereas `"$foo[@]"' evaluates to `"$foo[1]" "$foo[2]" ...'. For
associative arrays, `[*]' or `[@]' evaluate to all the values, in no
particular order. Note that this does not substitute the keys; see the
documentation for the `k' flag under *Note Parameter Expansion:: for
complete details. When an array parameter is referenced as `$NAME'
(with no subscript) it evaluates to `$NAME[*]', unless the KSH_ARRAYS
option is set in which case it evaluates to `${NAME[0]}' (for an
associative array, this means the value of the key `0', which may not
exist even if there are values for other keys).
A subscript of the form `[EXP1,EXP2]' selects all elements in the range
EXP1 to EXP2, inclusive. (Associative arrays are unordered, and so do
not support ranges.) If one of the subscripts evaluates to a negative
number, say -N, then the Nth element from the end of the array is used.
Thus `$foo[-3]' is the third element from the end of the array foo, and
`$foo[1,-1]' is the same as `$foo[*]'.
Subscripting may also be performed on non-array values, in which case
the subscripts specify a substring to be extracted. For example, if
FOO is set to `foobar', then `echo $FOO[2,5]' prints `ooba'.
15.2.2 Array Element Assignment
-------------------------------
A subscript may be used on the left side of an assignment like so:
NAME[EXP]=VALUE
In this form of assignment the element or range specified by EXP is
replaced by the expression on the right side. An array (but not an
associative array) may be created by assignment to a range or element.
Arrays do not nest, so assigning a parenthesized list of values to an
element or range changes the number of elements in the array, shifting
the other elements to accommodate the new values. (This is not
supported for associative arrays.)
This syntax also works as an argument to the typeset command:
typeset "NAME[EXP]"=VALUE
The VALUE may _not_ be a parenthesized list in this case; only
single-element assignments may be made with typeset. Note that quotes
are necessary in this case to prevent the brackets from being
interpreted as filename generation operators. The noglob precommand
modifier could be used instead.
To delete an element of an ordinary array, assign `()' to that element.
To delete an element of an associative array, use the unset command:
unset "NAME[EXP]"
15.2.3 Subscript Flags
----------------------
If the opening bracket, or the comma in a range, in any subscript
expression is directly followed by an opening parenthesis, the string up
to the matching closing one is considered to be a list of flags, as in
`NAME[(FLAGS)EXP]'.
The flags s, n and b take an argument; the delimiter is shown below as
`:', but any character, or the matching pairs `(...)', `{...}',
`[...]', or `<...>', may be used.
The flags currently understood are:
w
If the parameter subscripted is a scalar then this flag makes
subscripting work on words instead of characters. The default word
separator is whitespace. This flag may not be used with the i or
I flag.
s:STRING:
This gives the STRING that separates words (for use with the w
flag). The delimiter character : is arbitrary; see above.
p
Recognize the same escape sequences as the print builtin in the
string argument of a subsequent `s' flag.
f
If the parameter subscripted is a scalar then this flag makes
subscripting work on lines instead of characters, i.e. with
elements separated by newlines. This is a shorthand for `pws:\n:'.
r
Reverse subscripting: if this flag is given, the EXP is taken as a
pattern and the result is the first matching array element,
substring or word (if the parameter is an array, if it is a
scalar, or if it is a scalar and the `w' flag is given,
respectively). The subscript used is the number of the matching
element, so that pairs of subscripts such as `$foo[(r)??,3]' and
`$foo[(r)??,(r)f*]' are possible if the parameter is not an
associative array. If the parameter is an associative array, only
the value part of each pair is compared to the pattern, and the
result is that value.
If a search through an ordinary array failed, the search sets the
subscript to one past the end of the array, and hence
${array[(r)pattern]} will substitute the empty string. Thus the
success of a search can be tested by using the (i) flag, for
example (assuming the option KSH_ARRAYS is not in effect):
[[ ${array[(i)pattern]} -le ${#array} ]]
If KSH_ARRAYS is in effect, the -le should be replaced by -lt.
R
Like `r', but gives the last match. For associative arrays, gives
all possible matches. May be used for assigning to ordinary array
elements, but not for assigning to associative arrays. On
failure, for normal arrays this has the effect of returning the
element corresponding to subscript 0; this is empty unless one of
the options KSH_ARRAYS or KSH_ZERO_SUBSCRIPT is in effect.
Note that in subscripts with both `r' and `R' pattern characters
are active even if they were substituted for a parameter
(regardless of the setting of GLOB_SUBST which controls this
feature in normal pattern matching). The flag `e' can be added to
inhibit pattern matching. As this flag does not inhibit other
forms of substitution, care is still required; using a parameter
to hold the key has the desired effect:
key2='original key'
print ${array[(Re)$key2]}
i
Like `r', but gives the index of the match instead; this may not be
combined with a second argument. On the left side of an
assignment, behaves like `r'. For associative arrays, the key
part of each pair is compared to the pattern, and the first
matching key found is the result. On failure substitutes the
length of the array plus one, as discussed under the description
of `r', or the empty string for an associative array.
I
Like `i', but gives the index of the last match, or all possible
matching keys in an associative array. On failure substitutes 0,
or the empty string for an associative array. This flag is best
when testing for values or keys that do not exist.
k
If used in a subscript on an associative array, this flag causes
the keys to be interpreted as patterns, and returns the value for
the first key found where EXP is matched by the key. Note this
could be any such key as no ordering of associative arrays is
defined. This flag does not work on the left side of an
assignment to an associative array element. If used on another
type of parameter, this behaves like `r'.
K
On an associative array this is like `k' but returns all values
where EXP is matched by the keys. On other types of parameters
this has the same effect as `R'.
n:EXPR:
If combined with `r', `R', `i' or `I', makes them give the Nth or
Nth last match (if EXPR evaluates to N). This flag is ignored
when the array is associative. The delimiter character : is
arbitrary; see above.
b:EXPR:
If combined with `r', `R', `i' or `I', makes them begin at the Nth
or Nth last element, word, or character (if EXPR evaluates to N).
This flag is ignored when the array is associative. The delimiter
character : is arbitrary; see above.
e
This flag causes any pattern matching that would be performed on
the subscript to use plain string matching instead. Hence
`${array[(re)*]}' matches only the array element whose value is *.
Note that other forms of substitution such as parameter
substitution are not inhibited.
This flag can also be used to force * or @ to be interpreted as a
single key rather than as a reference to all values. It may be
used for either purpose on the left side of an assignment.
See _Parameter Expansion Flags_ (*Note Parameter Expansion::) for
additional ways to manipulate the results of array subscripting.
15.2.4 Subscript Parsing
------------------------
This discussion applies mainly to associative array key strings and to
patterns used for reverse subscripting (the `r', `R', `i', etc. flags),
but it may also affect parameter substitutions that appear as part of
an arithmetic expression in an ordinary subscript.
It is possible to avoid the use of subscripts in assignments to
associative array elements by using the syntax:
aa+=('key with "*strange*" characters' 'value string')
This adds a new key/value pair if the key is not already present, and
replaces the value for the existing key if it is.
The basic rule to remember when writing a subscript expression is that
all text between the opening `[' and the closing `]' is interpreted _as
if_ it were in double quotes (*Note Quoting::). However, unlike double
quotes which normally cannot nest, subscript expressions may appear
inside double-quoted strings or inside other subscript expressions (or
both!), so the rules have two important differences.
The first difference is that brackets (`[' and `]') must appear as
balanced pairs in a subscript expression unless they are preceded by a
backslash (`\'). Therefore, within a subscript expression (and unlike
true double-quoting) the sequence `\[' becomes `[', and similarly `\]'
becomes `]'. This applies even in cases where a backslash is not
normally required; for example, the pattern `[^[]' (to match any
character other than an open bracket) should be written `[^\[]' in a
reverse-subscript pattern. However, note that `\[^\[\]' and even
`\[^[]' mean the _same_ thing, because backslashes are always stripped
when they appear before brackets!
The same rule applies to parentheses (`(' and `)') and braces (`{' and
`}'): they must appear either in balanced pairs or preceded by a
backslash, and backslashes that protect parentheses or braces are
removed during parsing. This is because parameter expansions may be
surrounded by balanced braces, and subscript flags are introduced by
balanced parentheses.
The second difference is that a double-quote (`"') may appear as part
of a subscript expression without being preceded by a backslash, and
therefore that the two characters `\"' remain as two characters in the
subscript (in true double-quoting, `\"' becomes `"'). However, because
of the standard shell quoting rules, any double-quotes that appear must
occur in balanced pairs unless preceded by a backslash. This makes it
more difficult to write a subscript expression that contains an odd
number of double-quote characters, but the reason for this difference is
so that when a subscript expression appears inside true double-quotes,
one can still write `\"' (rather than `\\\"') for `"'.
To use an odd number of double quotes as a key in an assignment, use the
typeset builtin and an enclosing pair of double quotes; to refer to the
value of that key, again use double quotes:
typeset -A aa
typeset "aa[one\"two\"three\"quotes]"=QQQ
print "$aa[one\"two\"three\"quotes]"
It is important to note that the quoting rules do not change when a
parameter expansion with a subscript is nested inside another subscript
expression. That is, it is not necessary to use additional backslashes
within the inner subscript expression; they are removed only once, from
the innermost subscript outwards. Parameters are also expanded from the
innermost subscript first, as each expansion is encountered left to
right in the outer expression.
A further complication arises from a way in which subscript parsing is
_not_ different from double quote parsing. As in true double-quoting,
the sequences `\*', and `\@' remain as two characters when they appear
in a subscript expression. To use a literal `*' or `@' as an
associative array key, the `e' flag must be used:
typeset -A aa
aa[(e)*]=star
print $aa[(e)*]
A last detail must be considered when reverse subscripting is performed.
Parameters appearing in the subscript expression are first expanded and
then the complete expression is interpreted as a pattern. This has two
effects: first, parameters behave as if GLOB_SUBST were on (and it
cannot be turned off); second, backslashes are interpreted twice, once
when parsing the array subscript and again when parsing the pattern.
In a reverse subscript, it's necessary to use _four_ backslashes to
cause a single backslash to match literally in the pattern. For
complex patterns, it is often easiest to assign the desired pattern to
a parameter and then refer to that parameter in the subscript, because
then the backslashes, brackets, parentheses, etc., are seen only when
the complete expression is converted to a pattern. To match the value
of a parameter literally in a reverse subscript, rather than as a
pattern, use `${(q)NAME}' (*Note Parameter Expansion::) to quote the
expanded value.
Note that the `k' and `K' flags are reverse subscripting for an
ordinary array, but are _not_ reverse subscripting for an associative
array! (For an associative array, the keys in the array itself are
interpreted as patterns by those flags; the subscript is a plain string
in that case.)
One final note, not directly related to subscripting: the numeric names
of positional parameters (*Note Positional Parameters::) are parsed
specially, so for example `$2foo' is equivalent to `${2}foo'.
Therefore, to use subscript syntax to extract a substring from a
positional parameter, the expansion must be surrounded by braces; for
example, `${2[3,5]}' evaluates to the third through fifth characters of
the second positional parameter, but `$2[3,5]' is the entire second
parameter concatenated with the filename generation pattern `[3,5]'.
File: zsh.info, Node: Positional Parameters, Next: Local Parameters, Prev: Array Parameters, Up: Parameters
15.3 Positional Parameters
==========================
The positional parameters provide access to the command-line arguments
of a shell function, shell script, or the shell itself; see *Note
Invocation::, and also *Note Functions::. The parameter N, where N is
a number, is the Nth positional parameter. The parameters *, @ and
argv are arrays containing all the positional parameters; thus
`$argv[N]', etc., is equivalent to simply `$N'.
Positional parameters may be changed after the shell or function starts
by using the set builtin, by assigning to the argv array, or by direct
assignment of the form `N=VALUE' where N is the number of the
positional parameter to be changed. This also creates (with empty
values) any of the positions from 1 to N that do not already have
values. Note that, because the positional parameters form an array, an
array assignment of the form `N=(VALUE ...)' is allowed, and has the
effect of shifting all the values at positions greater than N by as
many positions as necessary to accommodate the new values.
File: zsh.info, Node: Local Parameters, Next: Parameters Set By The Shell, Prev: Positional Parameters, Up: Parameters
15.4 Local Parameters
=====================
Shell function executions delimit scopes for shell parameters.
(Parameters are dynamically scoped.) The typeset builtin, and its
alternative forms declare, integer, local and readonly (but not
export), can be used to declare a parameter as being local to the
innermost scope.
When a parameter is read or assigned to, the innermost existing
parameter of that name is used. (That is, the local parameter hides
any less-local parameter.) However, assigning to a non-existent
parameter, or declaring a new parameter with export, causes it to be
created in the _outer_most scope.
Local parameters disappear when their scope ends. unset can be used to
delete a parameter while it is still in scope; any outer parameter of
the same name remains hidden.
Special parameters may also be made local; they retain their special
attributes unless either the existing or the newly-created parameter
has the -h (hide) attribute. This may have unexpected effects: there
is no default value, so if there is no assignment at the point the
variable is made local, it will be set to an empty value (or zero in
the case of integers). The following:
typeset PATH=/new/directory:$PATH
is valid for temporarily allowing the shell or programmes called from
it to find the programs in /new/directory inside a function.
Note that the restriction in older versions of zsh that local parameters
were never exported has been removed.
File: zsh.info, Node: Parameters Set By The Shell, Next: Parameters Used By The Shell, Prev: Local Parameters, Up: Parameters
15.5 Parameters Set By The Shell
================================
The following parameters are automatically set by the shell:
! <S>
The process ID of the last command started in the background with
&, or put into the background with the bg builtin.
# <S>
The number of positional parameters in decimal. Note that some
confusion may occur with the syntax $#PARAM which substitutes the
length of PARAM. Use ${#} to resolve ambiguities. In particular,
the sequence `$#-...' in an arithmetic expression is interpreted as
the length of the parameter -, q.v.
ARGC <S> <Z>
Same as #.
$ <S>
The process ID of this shell. Note that this indicates the
original shell started by invoking zsh; all processes forked from
the shells without executing a new program, such as subshells
started by (...), substitute the same value.
- <S>
Flags supplied to the shell on invocation or by the set or setopt
commands.
* <S>
An array containing the positional parameters.
argv <S> <Z>
Same as *. Assigning to argv changes the local positional
parameters, but argv is _not_ itself a local parameter. Deleting
argv with unset in any function deletes it everywhere, although
only the innermost positional parameter array is deleted (so * and
@ in other scopes are not affected).
@ <S>
Same as argv[@], even when argv is not set.
? <S>
The exit status returned by the last command.
0 <S>
The name used to invoke the current shell. If the
FUNCTION_ARGZERO option is set, this is set temporarily within a
shell function to the name of the function, and within a sourced
script to the name of the script.
status <S> <Z>
Same as ?.
pipestatus <S> <Z>
An array containing the exit statuses returned by all commands in
the last pipeline.
_ <S>
The last argument of the previous command. Also, this parameter
is set in the environment of every command executed to the full
pathname of the command.
CPUTYPE
The machine type (microprocessor class or machine model), as
determined at run time.
EGID <S>
The effective group ID of the shell process. If you have
sufficient privileges, you may change the effective group ID of
the shell process by assigning to this parameter. Also (assuming
sufficient privileges), you may start a single command with a
different effective group ID by `(EGID=GID; command)'
EUID <S>
The effective user ID of the shell process. If you have sufficient
privileges, you may change the effective user ID of the shell
process by assigning to this parameter. Also (assuming sufficient
privileges), you may start a single command with a different
effective user ID by `(EUID=UID; command)'
ERRNO <S>
The value of errno (see man page errno(3)) as set by the most
recently failed system call. This value is system dependent and
is intended for debugging purposes. It is also useful with the
zsh/system module which allows the number to be turned into a name
or message.
GID <S>
The real group ID of the shell process. If you have sufficient
privileges, you may change the group ID of the shell process by
assigning to this parameter. Also (assuming sufficient
privileges), you may start a single command under a different
group ID by `(GID=GID; command)'
HISTCMD
The current history line number in an interactive shell, in other
words the line number for the command that caused $HISTCMD to be
read.
HOST
The current hostname.
LINENO <S>
The line number of the current line within the current script,
sourced file, or shell function being executed, whichever was
started most recently. Note that in the case of shell functions
the line number refers to the function as it appeared in the
original definition, not necessarily as displayed by the functions
builtin.
LOGNAME
If the corresponding variable is not set in the environment of the
shell, it is initialized to the login name corresponding to the
current login session. This parameter is exported by default but
this can be disabled using the typeset builtin.
MACHTYPE
The machine type (microprocessor class or machine model), as
determined at compile time.
OLDPWD
The previous working directory. This is set when the shell
initializes and whenever the directory changes.
OPTARG <S>
The value of the last option argument processed by the getopts
command.
OPTIND <S>
The index of the last option argument processed by the getopts
command.
OSTYPE
The operating system, as determined at compile time.
PPID <S>
The process ID of the parent of the shell. As for $$, the value
indicates the parent of the original shell and does not change in
subshells.
PWD
The present working directory. This is set when the shell
initializes and whenever the directory changes.
RANDOM <S>
A pseudo-random integer from 0 to 32767, newly generated each time
this parameter is referenced. The random number generator can be
seeded by assigning a numeric value to RANDOM.
The values of RANDOM form an intentionally-repeatable pseudo-random
sequence; subshells that reference RANDOM will result in identical
pseudo-random values unless the value of RANDOM is referenced or
seeded in the parent shell in between subshell invocations.
SECONDS <S>
The number of seconds since shell invocation. If this parameter
is assigned a value, then the value returned upon reference will
be the value that was assigned plus the number of seconds since
the assignment.
Unlike other special parameters, the type of the SECONDS parameter
can be changed using the typeset command. Only integer and one of
the floating point types are allowed. For example, `typeset -F
SECONDS' causes the value to be reported as a floating point
number. The value is available to microsecond accuracy, although
the shell may show more or fewer digits depending on the use of
typeset. See the documentation for the builtin typeset in *Note
Shell Builtin Commands:: for more details.
SHLVL <S>
Incremented by one each time a new shell is started.
signals
An array containing the names of the signals.
TRY_BLOCK_ERROR <S>
In an always block, indicates whether the preceding list of code
caused an error. The value is 1 to indicate an error, 0 otherwise.
It may be reset, clearing the error condition. See *Note Complex
Commands::
TTY
The name of the tty associated with the shell, if any.
TTYIDLE <S>
The idle time of the tty associated with the shell in seconds or
-1 if there is no such tty.
UID <S>
The real user ID of the shell process. If you have sufficient
privileges, you may change the user ID of the shell by assigning
to this parameter. Also (assuming sufficient privileges), you may
start a single command under a different user ID by `(UID=UID;
command)'
USERNAME <S>
The username corresponding to the real user ID of the shell
process. If you have sufficient privileges, you may change the
username (and also the user ID and group ID) of the shell by
assigning to this parameter. Also (assuming sufficient
privileges), you may start a single command under a different
username (and user ID and group ID) by `(USERNAME=USERNAME;
command)'
VENDOR
The vendor, as determined at compile time.
ZSH_NAME
Expands to the basename of the command used to invoke this instance
of zsh.
ZSH_PATCHLEVEL
The revision string for the version number of the ChangeLog file
in the zsh distribution. This is most useful in order to keep
track of versions of the shell during development between releases;
hence most users should not use it and should instead rely on
$ZSH_VERSION.
zsh_scheduled_events
See *Note The zsh/sched Module::.
ZSH_SUBSHELL
Readonly integer. Initially zero, incremented each time the shell
forks to create a subshell for executing code. Hence `(print
$ZSH_SUBSHELL)' and `print $(print $ZSH_SUBSHELL)' output 1, while
`( (print $ZSH_SUBSHELL) )' outputs 2.
ZSH_VERSION
The version number of the release of zsh.
File: zsh.info, Node: Parameters Used By The Shell, Prev: Parameters Set By The Shell, Up: Parameters
15.6 Parameters Used By The Shell
=================================
The following parameters are used by the shell.
In cases where there are two parameters with an upper- and lowercase
form of the same name, such as path and PATH, the lowercase form is an
array and the uppercase form is a scalar with the elements of the array
joined together by colons. These are similar to tied parameters
created via `typeset -T'. The normal use for the colon-separated form
is for exporting to the environment, while the array form is easier to
manipulate within the shell. Note that unsetting either of the pair
will unset the other; they retain their special properties when
recreated, and recreating one of the pair will recreate the other.
ARGV0
If exported, its value is used as the argv[0] of external commands.
Usually used in constructs like `ARGV0=emacs nethack'.
BAUD
The rate in bits per second at which data reaches the terminal.
The line editor will use this value in order to compensate for a
slow terminal by delaying updates to the display until necessary.
If the parameter is unset or the value is zero the compensation
mechanism is turned off. The parameter is not set by default.
This parameter may be profitably set in some circumstances, e.g.
for slow modems dialing into a communications server, or on a slow
wide area network. It should be set to the baud rate of the
slowest part of the link for best performance.
cdpath <S> <Z> (CDPATH <S>)
An array (colon-separated list) of directories specifying the
search path for the cd command.
COLUMNS <S>
The number of columns for this terminal session. Used for
printing select lists and for the line editor.
CORRECT_IGNORE
If set, is treated as a pattern during spelling correction. Any
potential correction that matches the pattern is ignored. For
example, if the value is `_*' then completion functions (which, by
convention, have names beginning with `_') will never be offered
as spelling corrections. The pattern does not apply the correction
of file names, as applied by the CORRECT_ALL option (so with the
example just given files beginning with `_' in the current
directory would still be completed).
DIRSTACKSIZE
The maximum size of the directory stack. If the stack gets larger
than this, it will be truncated automatically. This is useful
with the AUTO_PUSHD option.
ENV
If the ENV environment variable is set when zsh is invoked as sh
or ksh, $ENV is sourced after the profile scripts. The value of
ENV is subjected to parameter expansion, command substitution, and
arithmetic expansion before being interpreted as a pathname. Note
that ENV is _not_ used unless zsh is emulating `sh' or `ksh'.
FCEDIT
The default editor for the fc builtin. If FCEDIT is not set, the
parameter EDITOR is used; if that is not set either, a builtin
default, usually vi, is used.
fignore <S> <Z> (FIGNORE <S>)
An array (colon separated list) containing the suffixes of files
to be ignored during filename completion. However, if completion
only generates files with suffixes in this list, then these files
are completed anyway.
fpath <S> <Z> (FPATH <S>)
An array (colon separated list) of directories specifying the
search path for function definitions. This path is searched when
a function with the -u attribute is referenced. If an executable
file is found, then it is read and executed in the current
environment.
histchars <S>
Three characters used by the shell's history and lexical analysis
mechanism. The first character signals the start of a history
expansion (default `!'). The second character signals the start
of a quick history substitution (default `^'). The third
character is the comment character (default `#').
The characters must be in the ASCII character set; any attempt to
set histchars to characters with a locale-dependent meaning will be
rejected with an error message.
HISTCHARS <S> <Z>
Same as histchars. (Deprecated.)
HISTFILE
The file to save the history in when an interactive shell exits.
If unset, the history is not saved.
HISTSIZE <S>
The maximum number of events stored in the internal history list.
If you use the HIST_EXPIRE_DUPS_FIRST option, setting this value
larger than the SAVEHIST size will give you the difference as a
cushion for saving duplicated history events.
HOME <S>
The default argument for the cd command. This is not set
automatically by the shell in sh, ksh or csh emulation, but it is
typically present in the environment anyway, and if it becomes set
it has its usual special behaviour.
IFS <S>
Internal field separators (by default space, tab, newline and
NUL), that are used to separate words which result from command or
parameter expansion and words read by the read builtin. Any
characters from the set space, tab and newline that appear in the
IFS are called _IFS white space_. One or more IFS white space
characters or one non-IFS white space character together with any
adjacent IFS white space character delimit a field. If an IFS
white space character appears twice consecutively in the IFS, this
character is treated as if it were not an IFS white space
character.
If the parameter is unset, the default is used. Note this has a
different effect from setting the parameter to an empty string.
KEYTIMEOUT
The time the shell waits, in hundredths of seconds, for another
key to be pressed when reading bound multi-character sequences.
LANG <S>
This variable determines the locale category for any category not
specifically selected via a variable starting with `LC_'.
LC_ALL <S>
This variable overrides the value of the `LANG' variable and the
value of any of the other variables starting with `LC_'.
LC_COLLATE <S>
This variable determines the locale category for character
collation information within ranges in glob brackets and for
sorting.
LC_CTYPE <S>
This variable determines the locale category for character handling
functions. If the MULTIBYTE option is in effect this variable or
LANG should contain a value that reflects the character set in
use, even if it is a single-byte character set, unless only the
7-bit subset (ASCII) is used. For example, if the character set
is ISO-8859-1, a suitable value might be en_US.iso88591 (certain
Linux distributions) or en_US.ISO8859-1 (MacOS).
LC_MESSAGES <S>
This variable determines the language in which messages should be
written. Note that zsh does not use message catalogs.
LC_NUMERIC <S>
This variable affects the decimal point character and thousands
separator character for the formatted input/output functions and
string conversion functions. Note that zsh ignores this setting
when parsing floating point mathematical expressions.
LC_TIME <S>
This variable determines the locale category for date and time
formatting in prompt escape sequences.
LINES <S>
The number of lines for this terminal session. Used for printing
select lists and for the line editor.
LISTMAX
In the line editor, the number of matches to list without asking
first. If the value is negative, the list will be shown if it
spans at most as many lines as given by the absolute value. If
set to zero, the shell asks only if the top of the listing would
scroll off the screen.
LOGCHECK
The interval in seconds between checks for login/logout activity
using the watch parameter.
MAIL
If this parameter is set and mailpath is not set, the shell looks
for mail in the specified file.
MAILCHECK
The interval in seconds between checks for new mail.
mailpath <S> <Z> (MAILPATH <S>)
An array (colon-separated list) of filenames to check for new
mail. Each filename can be followed by a `?' and a message that
will be printed. The message will undergo parameter expansion,
command substitution and arithmetic expansion with the variable $_
defined as the name of the file that has changed. The default
message is `You have new mail'. If an element is a directory
instead of a file the shell will recursively check every file in
every subdirectory of the element.
manpath <S> <Z> (MANPATH <S> <Z>)
An array (colon-separated list) whose value is not used by the
shell. The manpath array can be useful, however, since setting it
also sets MANPATH, and vice versa.
module_path <S> <Z> (MODULE_PATH <S>)
An array (colon-separated list) of directories that zmodload
searches for dynamically loadable modules. This is initialized to
a standard pathname, usually `/usr/local/lib/zsh/$ZSH_VERSION'.
(The `/usr/local/lib' part varies from installation to
installation.) For security reasons, any value set in the
environment when the shell is started will be ignored.
These parameters only exist if the installation supports dynamic
module loading.
NULLCMD <S>
The command name to assume if a redirection is specified with no
command. Defaults to cat. For `sh'/`ksh' behavior, change this
to :. For `csh'-like behavior, unset this parameter; the shell
will print an error message if null commands are entered.
path <S> <Z> (PATH <S>)
An array (colon-separated list) of directories to search for
commands. When this parameter is set, each directory is scanned
and all files found are put in a hash table.
POSTEDIT <S>
This string is output whenever the line editor exits. It usually
contains termcap strings to reset the terminal.
PROMPT <S> <Z>
PROMPT2 <S> <Z>
PROMPT3 <S> <Z>
PROMPT4 <S> <Z>
Same as PS1, PS2, PS3 and PS4, respectively.
prompt <S> <Z>
Same as PS1.
PROMPT_EOL_MARK
When the PROMPT_CR and PROMPT_SP options are set, the
PROMPT_EOL_MARK parameter can be used to customize how the end of
partial lines are shown. This parameter undergoes prompt
expansion, with the PROMPT_PERCENT option set. If not set or
empty, the default behavior is equivalent to the value
`%B%S%#%s%b'.
PS1 <S>
The primary prompt string, printed before a command is read. It
undergoes a special form of expansion before being displayed; see
*Note Prompt Expansion::. The default is `%m%# '.
PS2 <S>
The secondary prompt, printed when the shell needs more information
to complete a command. It is expanded in the same way as PS1.
The default is `%_> ', which displays any shell constructs or
quotation marks which are currently being processed.
PS3 <S>
Selection prompt used within a select loop. It is expanded in the
same way as PS1. The default is `?# '.
PS4 <S>
The execution trace prompt. Default is `+%N:%i> ', which displays
the name of the current shell structure and the line number within
it. In sh or ksh emulation, the default is `+ '.
psvar <S> <Z> (PSVAR <S>)
An array (colon-separated list) whose first nine values can be
used in PROMPT strings. Setting psvar also sets PSVAR, and vice
versa.
READNULLCMD <S>
The command name to assume if a single input redirection is
specified with no command. Defaults to more.
REPORTTIME
If nonnegative, commands whose combined user and system execution
times (measured in seconds) are greater than this value have timing
statistics printed for them.
REPLY
This parameter is reserved by convention to pass string values
between shell scripts and shell builtins in situations where a
function call or redirection are impossible or undesirable. The
read builtin and the select complex command may set REPLY, and
filename generation both sets and examines its value when
evaluating certain expressions. Some modules also employ REPLY
for similar purposes.
reply
As REPLY, but for array values rather than strings.
RPROMPT <S>
RPS1 <S>
This prompt is displayed on the right-hand side of the screen when
the primary prompt is being displayed on the left. This does not
work if the SINGLELINEZLE option is set. It is expanded in the
same way as PS1.
RPROMPT2 <S>
RPS2 <S>
This prompt is displayed on the right-hand side of the screen when
the secondary prompt is being displayed on the left. This does
not work if the SINGLELINEZLE option is set. It is expanded in
the same way as PS2.
SAVEHIST
The maximum number of history events to save in the history file.
SPROMPT <S>
The prompt used for spelling correction. The sequence `%R'
expands to the string which presumably needs spelling correction,
and `%r' expands to the proposed correction. All other prompt
escapes are also allowed.
STTY
If this parameter is set in a command's environment, the shell
runs the stty command with the value of this parameter as
arguments in order to set up the terminal before executing the
command. The modes apply only to the command, and are reset when
it finishes or is suspended. If the command is suspended and
continued later with the fg or wait builtins it will see the modes
specified by STTY, as if it were not suspended. This
(intentionally) does not apply if the command is continued via
`kill -CONT'. STTY is ignored if the command is run in the
background, or if it is in the environment of the shell but not
explicitly assigned to in the input line. This avoids running stty
at every external command by accidentally exporting it. Also note
that STTY should not be used for window size specifications; these
will not be local to the command.
TERM <S>
The type of terminal in use. This is used when looking up termcap
sequences. An assignment to TERM causes zsh to re-initialize the
terminal, even if the value does not change (e.g., `TERM=$TERM').
It is necessary to make such an assignment upon any change to the
terminal definition database or terminal type in order for the new
settings to take effect.
TIMEFMT
The format of process time reports with the time keyword. The
default is `%E real %U user %S system %P %J'. Recognizes the
following escape sequences, although not all may be available on
all systems, and some that are available may not be useful:
%%
A `%'.
%U
CPU seconds spent in user mode.
%S
CPU seconds spent in kernel mode.
%E
Elapsed time in seconds.
%P
The CPU percentage, computed as (100*%U+%S)/%E.
%W
Number of times the process was swapped.
%X
The average amount in (shared) text space used in Kbytes.
%D
The average amount in (unshared) data/stack space used in
Kbytes.
%K
The total space used (%X+%D) in Kbytes.
%M
The maximum memory the process had in use at any time in
Kbytes.
%F
The number of major page faults (page needed to be brought
from disk).
%R
The number of minor page faults.
%I
The number of input operations.
%O
The number of output operations.
%r
The number of socket messages received.
%s
The number of socket messages sent.
%k
The number of signals received.
%w
Number of voluntary context switches (waits).
%c
Number of involuntary context switches.
%J
The name of this job.
A star may be inserted between the percent sign and flags printing
time. This cause the time to be printed in `HH:MM:SS.TTT' format
(hours and minutes are only printed if they are not zero).
TMOUT
If this parameter is nonzero, the shell will receive an ALRM
signal if a command is not entered within the specified number of
seconds after issuing a prompt. If there is a trap on SIGALRM, it
will be executed and a new alarm is scheduled using the value of
the TMOUT parameter after executing the trap. If no trap is set,
and the idle time of the terminal is not less than the value of the
TMOUT parameter, zsh terminates. Otherwise a new alarm is
scheduled to TMOUT seconds after the last keypress.
TMPPREFIX
A pathname prefix which the shell will use for all temporary files.
Note that this should include an initial part for the file name as
well as any directory names. The default is `/tmp/zsh'.
watch <S> <Z> (WATCH <S>)
An array (colon-separated list) of login/logout events to report.
If it contains the single word `all', then all login/logout events
are reported. If it contains the single word `notme', then all
events are reported as with `all' except $USERNAME. An entry in
this list may consist of a username, an `@' followed by a remote
hostname, and a `%' followed by a line (tty). Any or all of these
components may be present in an entry; if a login/logout event
matches all of them, it is reported.
WATCHFMT
The format of login/logout reports if the watch parameter is set.
Default is `%n has %a %l from %m'. Recognizes the following
escape sequences:
%n
The name of the user that logged in/out.
%a
The observed action, i.e. "logged on" or "logged off".
%l
The line (tty) the user is logged in on.
%M
The full hostname of the remote host.
%m
The hostname up to the first `.'. If only the IP address is
available or the utmp field contains the name of an X-windows
display, the whole name is printed.
_NOTE:_ The `%m' and `%M' escapes will work only if there is
a host name field in the utmp on your machine. Otherwise
they are treated as ordinary strings.
%S (%s)
Start (stop) standout mode.
%U (%u)
Start (stop) underline mode.
%B (%b)
Start (stop) boldface mode.
%t
%@
The time, in 12-hour, am/pm format.
%T
The time, in 24-hour format.
%w
The date in `DAY-DD' format.
%W
The date in `MM/DD/YY' format.
%D
The date in `YY-MM-DD' format.
%(X:TRUE-TEXT:FALSE-TEXT)
Specifies a ternary expression. The character following the
X is arbitrary; the same character is used to separate the
text for the "true" result from that for the "false" result.
Both the separator and the right parenthesis may be escaped
with a backslash. Ternary expressions may be nested.
The test character X may be any one of `l', `n', `m' or `M',
which indicate a `true' result if the corresponding escape
sequence would return a non-empty value; or it may be `a',
which indicates a `true' result if the watched user has
logged in, or `false' if he has logged out. Other characters
evaluate to neither true nor false; the entire expression is
omitted in this case.
If the result is `true', then the TRUE-TEXT is formatted
according to the rules above and printed, and the FALSE-TEXT
is skipped. If `false', the TRUE-TEXT is skipped and the
FALSE-TEXT is formatted and printed. Either or both of the
branches may be empty, but both separators must be present in
any case.
WORDCHARS <S>
A list of non-alphanumeric characters considered part of a word by
the line editor.
ZBEEP
If set, this gives a string of characters, which can use all the
same codes as the bindkey command as described in *Note The
zsh/zle Module::, that will be output to the terminal instead of
beeping. This may have a visible instead of an audible effect;
for example, the string `\e[?5h\e[?5l' on a vt100 or xterm will
have the effect of flashing reverse video on and off (if you
usually use reverse video, you should use the string
`\e[?5l\e[?5h' instead). This takes precedence over the NOBEEP
option.
ZDOTDIR
The directory to search for shell startup files (.zshrc, etc), if
not $HOME.
ZLE_REMOVE_SUFFIX_CHARS
ZLE_SPACE_SUFFIX_CHARS
These parameters are used by the line editor. In certain
circumstances suffixes (typically space or slash) added by the
completion system will be removed automatically, either because
the next editing command was not an insertable character, or
because the character was marked as requiring the suffix to be
removed.
These variables can contain the sets of characters that will cause
the suffix to be removed. If ZLE_REMOVE_SUFFIX_CHARS is set, those
characters will cause the suffix to be removed; if
ZLE_SPACE_SUFFIX_CHARS is set, those characters will cause the
suffix to be removed and replaced by a space.
If ZLE_REMOVE_SUFFIX_CHARS is not set, the default behaviour is
equivalent to:
ZLE_REMOVE_SUFFIX_CHARS=$' \t\n;&|'
If ZLE_REMOVE_SUFFIX_CHARS is set but is empty, no characters have
this behaviour. ZLE_SPACE_SUFFIX_CHARS takes precedence, so that
the following:
ZLE_SPACE_SUFFIX_CHARS=$'&|'
causes the characters `&' and `|' to remove the suffix but to
replace it with a space.
To illustrate the difference, suppose that the option
AUTO_REMOVE_SLASH is in effect and the directory DIR has just been
completed, with an appended /, following which the user types `&'.
The default result is `DIR&'. With ZLE_REMOVE_SUFFIX_CHARS set
but without including `&' the result is `DIR/&'. With
ZLE_SPACE_SUFFIX_CHARS set to include `&' the result is `DIR &'.
Note that certain completions may provide their own suffix removal
or replacement behaviour which overrides the values described here.
See the completion system documentation in *Note Completion
System::.
File: zsh.info, Node: Options, Next: Shell Builtin Commands, Prev: Parameters, Up: Top
16 Options
**********
* Menu:
* Specifying Options::
* Description of Options::
* Option Aliases::
* Single Letter Options::
File: zsh.info, Node: Specifying Options, Next: Description of Options, Up: Options
16.1 Specifying Options
=======================
Options are primarily referred to by name. These names are case
insensitive and underscores are ignored. For example, `allexport' is
equivalent to `A__lleXP_ort'.
The sense of an option name may be inverted by preceding it with `no',
so `setopt No_Beep' is equivalent to `unsetopt beep'. This inversion
can only be done once, so `nonobeep' is _not_ a synonym for `beep'.
Similarly, `tify' is not a synonym for `nonotify' (the inversion of
`notify').
Some options also have one or more single letter names. There are two
sets of single letter options: one used by default, and another used to
emulate `sh'/`ksh' (used when the SH_OPTION_LETTERS option is set).
The single letter options can be used on the shell command line, or
with the set, setopt and unsetopt builtins, as normal Unix options
preceded by `-'.
The sense of the single letter options may be inverted by using `+'
instead of `-'. Some of the single letter option names refer to an
option being off, in which case the inversion of that name refers to
the option being on. For example, `+n' is the short name of `exec', and
`-n' is the short name of its inversion, `noexec'.
In strings of single letter options supplied to the shell at startup,
trailing whitespace will be ignored; for example the string `-f '
will be treated just as `-f', but the string `-f i' is an error. This
is because many systems which implement the `#!' mechanism for calling
scripts do not strip trailing whitespace.
File: zsh.info, Node: Description of Options, Next: Option Aliases, Prev: Specifying Options, Up: Options
16.2 Description of Options
===========================
In the following list, options set by default in all emulations are
marked <D>; those set by default only in csh, ksh, sh, or zsh
emulations are marked <C>, <K>, <S>, <Z> as appropriate. When listing
options (by `setopt', `unsetopt', `set -o' or `set +o'), those turned
on by default appear in the list prefixed with `no'. Hence (unless
KSH_OPTION_PRINT is set), `setopt' shows all options whose settings are
changed from the default.
16.2.1 Changing Directories
---------------------------
AUTO_CD (-J)
If a command is issued that can't be executed as a normal command,
and the command is the name of a directory, perform the cd command
to that directory.
AUTO_PUSHD (-N)
Make cd push the old directory onto the directory stack.
CDABLE_VARS (-T)
If the argument to a cd command (or an implied cd with the AUTO_CD
option set) is not a directory, and does not begin with a slash,
try to expand the expression as if it were preceded by a `~' (see
*Note Filename Expansion::).
CHASE_DOTS
When changing to a directory containing a path segment `..' which
would otherwise be treated as canceling the previous segment in
the path (in other words, `foo/..' would be removed from the path,
or if `..' is the first part of the path, the last part of $PWD
would be deleted), instead resolve the path to the physical
directory. This option is overridden by CHASE_LINKS.
For example, suppose /foo/bar is a link to the directory /alt/rod.
Without this option set, `cd /foo/bar/..' changes to /foo; with it
set, it changes to /alt. The same applies if the current directory
is /foo/bar and `cd ..' is used. Note that all other symbolic
links in the path will also be resolved.
CHASE_LINKS (-w)
Resolve symbolic links to their true values when changing
directory. This also has the effect of CHASE_DOTS, i.e. a `..'
path segment will be treated as referring to the physical parent,
even if the preceding path segment is a symbolic link.
PUSHD_IGNORE_DUPS
Don't push multiple copies of the same directory onto the
directory stack.
PUSHD_MINUS
Exchanges the meanings of `+' and `-' when used with a number to
specify a directory in the stack.
PUSHD_SILENT (-E)
Do not print the directory stack after pushd or popd.
PUSHD_TO_HOME (-D)
Have pushd with no arguments act like `pushd $HOME'.
16.2.2 Completion
-----------------
ALWAYS_LAST_PROMPT <D>
If unset, key functions that list completions try to return to the
last prompt if given a numeric argument. If set these functions
try to return to the last prompt if given _no_ numeric argument.
ALWAYS_TO_END
If a completion is performed with the cursor within a word, and a
full completion is inserted, the cursor is moved to the end of the
word. That is, the cursor is moved to the end of the word if
either a single match is inserted or menu completion is performed.
AUTO_LIST (-9) <D>
Automatically list choices on an ambiguous completion.
AUTO_MENU <D>
Automatically use menu completion after the second consecutive
request for completion, for example by pressing the tab key
repeatedly. This option is overridden by MENU_COMPLETE.
AUTO_NAME_DIRS
Any parameter that is set to the absolute name of a directory
immediately becomes a name for that directory, that will be used
by the `%~' and related prompt sequences, and will be available
when completion is performed on a word starting with `~'.
(Otherwise, the parameter must be used in the form `~PARAM' first.)
AUTO_PARAM_KEYS <D>
If a parameter name was completed and a following character
(normally a space) automatically inserted, and the next character
typed is one of those that have to come directly after the name
(like `}', `:', etc.), the automatically added character is
deleted, so that the character typed comes immediately after the
parameter name. Completion in a brace expansion is affected
similarly: the added character is a `,', which will be removed if
`}' is typed next.
AUTO_PARAM_SLASH <D>
If a parameter is completed whose content is the name of a
directory, then add a trailing slash instead of a space.
AUTO_REMOVE_SLASH <D>
When the last character resulting from a completion is a slash and
the next character typed is a word delimiter, a slash, or a
character that ends a command (such as a semicolon or an
ampersand), remove the slash.
BASH_AUTO_LIST
On an ambiguous completion, automatically list choices when the
completion function is called twice in succession. This takes
precedence over AUTO_LIST. The setting of LIST_AMBIGUOUS is
respected. If AUTO_MENU is set, the menu behaviour will then start
with the third press. Note that this will not work with
MENU_COMPLETE, since repeated completion calls immediately cycle
through the list in that case.
COMPLETE_ALIASES
Prevents aliases on the command line from being internally
substituted before completion is attempted. The effect is to make
the alias a distinct command for completion purposes.
COMPLETE_IN_WORD
If unset, the cursor is set to the end of the word if completion is
started. Otherwise it stays there and completion is done from both
ends.
GLOB_COMPLETE
When the current word has a glob pattern, do not insert all the
words resulting from the expansion but generate matches as for
completion and cycle through them like MENU_COMPLETE. The matches
are generated as if a `*' was added to the end of the word, or
inserted at the cursor when COMPLETE_IN_WORD is set. This
actually uses pattern matching, not globbing, so it works not only
for files but for any completion, such as options, user names, etc.
Note that when the pattern matcher is used, matching control (for
example, case-insensitive or anchored matching) cannot be used.
This limitation only applies when the current word contains a
pattern; simply turning on the GLOB_COMPLETE option does not have
this effect.
HASH_LIST_ALL <D>
Whenever a command completion is attempted, make sure the entire
command path is hashed first. This makes the first completion
slower.
LIST_AMBIGUOUS <D>
This option works when AUTO_LIST or BASH_AUTO_LIST is also set.
If there is an unambiguous prefix to insert on the command line,
that is done without a completion list being displayed; in other
words, auto-listing behaviour only takes place when nothing would
be inserted. In the case of BASH_AUTO_LIST, this means that the
list will be delayed to the third call of the function.
LIST_BEEP <D>
Beep on an ambiguous completion. More accurately, this forces the
completion widgets to return status 1 on an ambiguous completion,
which causes the shell to beep if the option BEEP is also set;
this may be modified if completion is called from a user-defined
widget.
LIST_PACKED
Try to make the completion list smaller (occupying less lines) by
printing the matches in columns with different widths.
LIST_ROWS_FIRST
Lay out the matches in completion lists sorted horizontally, that
is, the second match is to the right of the first one, not under
it as usual.
LIST_TYPES (-X) <D>
When listing files that are possible completions, show the type of
each file with a trailing identifying mark.
MENU_COMPLETE (-Y)
On an ambiguous completion, instead of listing possibilities or
beeping, insert the first match immediately. Then when completion
is requested again, remove the first match and insert the second
match, etc. When there are no more matches, go back to the first
one again. reverse-menu-complete may be used to loop through the
list in the other direction. This option overrides AUTO_MENU.
REC_EXACT (-S)
In completion, recognize exact matches even if they are ambiguous.
16.2.3 Expansion and Globbing
-----------------------------
BAD_PATTERN (+2) <C> <Z>
If a pattern for filename generation is badly formed, print an
error message. (If this option is unset, the pattern will be left
unchanged.)
BARE_GLOB_QUAL <Z>
In a glob pattern, treat a trailing set of parentheses as a
qualifier list, if it contains no `|', `(' or (if special) `~'
characters. See *Note Filename Generation::.
BRACE_CCL
Expand expressions in braces which would not otherwise undergo
brace expansion to a lexically ordered list of all the characters.
See *Note Brace Expansion::.
CASE_GLOB <D>
Make globbing (filename generation) sensitive to case. Note that
other uses of patterns are always sensitive to case. If the
option is unset, the presence of any character which is special to
filename generation will cause case-insensitive matching. For
example, cvs(/) can match the directory CVS owing to the presence
of the globbing flag (unless the option BARE_GLOB_QUAL is unset).
CASE_MATCH <D>
Make regular expressions using the zsh/regex module (including
matches with =~) sensitive to case.
CSH_NULL_GLOB <C>
If a pattern for filename generation has no matches, delete the
pattern from the argument list; do not report an error unless all
the patterns in a command have no matches. Overrides NOMATCH.
EQUALS <Z>
Perform = filename expansion. (See *Note Filename Expansion::.)
EXTENDED_GLOB
Treat the `#', `~' and `^' characters as part of patterns for
filename generation, etc. (An initial unquoted `~' always
produces named directory expansion.)
GLOB (+F, ksh: +f) <D>
Perform filename generation (globbing). (See *Note Filename
Generation::.)
GLOB_ASSIGN <C>
If this option is set, filename generation (globbing) is performed
on the right hand side of scalar parameter assignments of the form
`NAME=PATTERN (e.g. `foo=*'). If the result has more than one
word the parameter will become an array with those words as
arguments. This option is provided for backwards compatibility
only: globbing is always performed on the right hand side of array
assignments of the form `NAME=(VALUE)' (e.g. `foo=(*)') and this
form is recommended for clarity; with this option set, it is not
possible to predict whether the result will be an array or a
scalar.
GLOB_DOTS (-4)
Do not require a leading `.' in a filename to be matched
explicitly.
GLOB_SUBST <C> <K> <S>
Treat any characters resulting from parameter expansion as being
eligible for file expansion and filename generation, and any
characters resulting from command substitution as being eligible
for filename generation. Braces (and commas in between) do not
become eligible for expansion.
HIST_SUBST_PATTERN
Substitutions using the :s and :& history modifiers are performed
with pattern matching instead of string matching. This occurs
wherever history modifiers are valid, including glob qualifiers
and parameters. See *Note Modifiers::.
IGNORE_BRACES (-I) <S>
Do not perform brace expansion.
KSH_GLOB <K>
In pattern matching, the interpretation of parentheses is affected
by a preceding `@', `*', `+', `?' or `!'. See *Note Filename
Generation::.
MAGIC_EQUAL_SUBST
All unquoted arguments of the form `ANYTHING=EXPRESSION' appearing
after the command name have filename expansion (that is, where
EXPRESSION has a leading `~' or `=') performed on EXPRESSION as if
it were a parameter assignment. The argument is not otherwise
treated specially; it is passed to the command as a single
argument, and not used as an actual parameter assignment. For
example, in echo foo=~/bar:~/rod, both occurrences of ~ would be
replaced. Note that this happens anyway with typeset and similar
statements.
This option respects the setting of the KSH_TYPESET option. In
other words, if both options are in effect, arguments looking like
assignments will not undergo word splitting.
MARK_DIRS (-8, ksh: -X)
Append a trailing `/' to all directory names resulting from
filename generation (globbing).
MULTIBYTE <C> <K> <Z>
Respect multibyte characters when found in strings. When this
option is set, strings are examined using the system library to
determine how many bytes form a character, depending on the
current locale. This affects the way characters are counted in
pattern matching, parameter values and various delimiters.
The option is on by default if the shell was compiled with
MULTIBYTE_SUPPORT except in sh emulation; otherwise it is off by
default and has no effect if turned on. The mode is off in sh
emulation for compatibility but for interactive use may need to be
turned on if the terminal interprets multibyte characters.
If the option is off a single byte is always treated as a single
character. This setting is designed purely for examining strings
known to contain raw bytes or other values that may not be
characters in the current locale. It is not necessary to unset
the option merely because the character set for the current locale
does not contain multibyte characters.
The option does not affect the shell's editor, which always uses
the locale to determine multibyte characters. This is because the
character set displayed by the terminal emulator is independent of
shell settings.
NOMATCH (+3) <C> <Z>
If a pattern for filename generation has no matches, print an
error, instead of leaving it unchanged in the argument list. This
also applies to file expansion of an initial `~' or `='.
NULL_GLOB (-G)
If a pattern for filename generation has no matches, delete the
pattern from the argument list instead of reporting an error.
Overrides NOMATCH.
NUMERIC_GLOB_SORT
If numeric filenames are matched by a filename generation pattern,
sort the filenames numerically rather than lexicographically.
RC_EXPAND_PARAM (-P)
Array expansions of the form `FOO${XX}BAR', where the parameter XX
is set to (A B C), are substituted with `FOOABAR FOOBBAR FOOCBAR'
instead of the default `FOOA B CBAR'. Note that an empty array
will therefore cause all arguments to be removed.
REMATCH_PCRE <Z>
If set, regular expression matching with the =~ operator will use
Perl-Compatible Regular Expressions from the PCRE library, if
available. If not set, regular expressions will use the extended
regexp syntax provided by the system libraries.
SH_GLOB <K> <S>
Disables the special meaning of `(', `|', `)' and '<' for globbing
the result of parameter and command substitutions, and in some
other places where the shell accepts patterns. This option is set
by default if zsh is invoked as sh or ksh.
UNSET (+u, ksh: +u) <K> <S> <Z>
Treat unset parameters as if they were empty when substituting.
Otherwise they are treated as an error.
WARN_CREATE_GLOBAL
Print a warning message when a global parameter is created in a
function by an assignment. This often indicates that a parameter
has not been declared local when it should have been. Parameters
explicitly declared global from within a function using typeset -g
do not cause a warning. Note that there is no warning when a
local parameter is assigned to in a nested function, which may
also indicate an error.
16.2.4 History
--------------
APPEND_HISTORY <D>
If this is set, zsh sessions will append their history list to the
history file, rather than replace it. Thus, multiple parallel zsh
sessions will all have the new entries from their history lists
added to the history file, in the order that they exit. The file
will still be periodically re-written to trim it when the number
of lines grows 20% beyond the value specified by $SAVEHIST (see
also the HIST_SAVE_BY_COPY option).
BANG_HIST (+K) <C> <Z>
Perform textual history expansion, `csh'-style, treating the
character `!' specially.
EXTENDED_HISTORY <C>
Save each command's beginning timestamp (in seconds since the
epoch) and the duration (in seconds) to the history file. The
format of this prefixed data is:
`:<BEGINNING TIME>:<ELAPSED SECONDS>:<COMMAND>'.
HIST_ALLOW_CLOBBER
Add `|' to output redirections in the history. This allows history
references to clobber files even when CLOBBER is unset.
HIST_BEEP <D>
Beep when an attempt is made to access a history entry which isn't
there.
HIST_EXPIRE_DUPS_FIRST
If the internal history needs to be trimmed to add the current
command line, setting this option will cause the oldest history
event that has a duplicate to be lost before losing a unique event
from the list. You should be sure to set the value of HISTSIZE to
a larger number than SAVEHIST in order to give you some room for
the duplicated events, otherwise this option will behave just like
HIST_IGNORE_ALL_DUPS once the history fills up with unique events.
HIST_FCNTL_LOCK
When writing out the history file, by default zsh uses ad-hoc file
locking to avoid known problems with locking on some operating
systems. With this option locking is done by means of the
system's fcntl call, where this method is available. On recent
operating systems this may provide better performance, in
particular avoiding history corruption when files are stored on
NFS.
HIST_FIND_NO_DUPS
When searching for history entries in the line editor, do not
display duplicates of a line previously found, even if the
duplicates are not contiguous.
HIST_IGNORE_ALL_DUPS
If a new command line being added to the history list duplicates an
older one, the older command is removed from the list (even if it
is not the previous event).
HIST_IGNORE_DUPS (-h)
Do not enter command lines into the history list if they are
duplicates of the previous event.
HIST_IGNORE_SPACE (-g)
Remove command lines from the history list when the first
character on the line is a space, or when one of the expanded
aliases contains a leading space. Note that the command lingers
in the internal history until the next command is entered before
it vanishes, allowing you to briefly reuse or edit the line. If
you want to make it vanish right away without entering another
command, type a space and press return.
HIST_NO_FUNCTIONS
Remove function definitions from the history list. Note that the
function lingers in the internal history until the next command is
entered before it vanishes, allowing you to briefly reuse or edit
the definition.
HIST_NO_STORE
Remove the history (fc -l) command from the history list when
invoked. Note that the command lingers in the internal history
until the next command is entered before it vanishes, allowing you
to briefly reuse or edit the line.
HIST_REDUCE_BLANKS
Remove superfluous blanks from each command line being added to
the history list.
HIST_SAVE_BY_COPY <D>
When the history file is re-written, we normally write out a copy
of the file named $HISTFILE.new and then rename it over the old
one. However, if this option is unset, we instead truncate the old
history file and write out the new version in-place. If one of the
history-appending options is enabled, this option only has an
effect when the enlarged history file needs to be re-written to
trim it down to size. Disable this only if you have special
needs, as doing so makes it possible to lose history entries if
zsh gets interrupted during the save.
When writing out a copy of the history file, zsh preserves the old
file's permissions and group information, but will refuse to write
out a new file if it would change the history file's owner.
HIST_SAVE_NO_DUPS
When writing out the history file, older commands that duplicate
newer ones are omitted.
HIST_VERIFY
Whenever the user enters a line with history expansion, don't
execute the line directly; instead, perform history expansion and
reload the line into the editing buffer.
INC_APPEND_HISTORY
This options works like APPEND_HISTORY except that new history
lines are added to the $HISTFILE incrementally (as soon as they are
entered), rather than waiting until the shell exits. The file
will still be periodically re-written to trim it when the number
of lines grows 20% beyond the value specified by $SAVEHIST (see
also the HIST_SAVE_BY_COPY option).
SHARE_HISTORY <K>
This option both imports new commands from the history file, and
also causes your typed commands to be appended to the history file
(the latter is like specifying INC_APPEND_HISTORY). The history
lines are also output with timestamps ala EXTENDED_HISTORY (which
makes it easier to find the spot where we left off reading the
file after it gets re-written).
By default, history movement commands visit the imported lines as
well as the local lines, but you can toggle this on and off with
the set-local-history zle binding. It is also possible to create
a zle widget that will make some commands ignore imported
commands, and some include them.
If you find that you want more control over when commands get
imported, you may wish to turn SHARE_HISTORY off,
INC_APPEND_HISTORY on, and then manually import commands whenever
you need them using `fc -RI'.
16.2.5 Initialisation
---------------------
ALL_EXPORT (-a, ksh: -a)
All parameters subsequently defined are automatically exported.
GLOBAL_EXPORT (<Z>)
If this option is set, passing the -x flag to the builtins declare,
float, integer, readonly and typeset (but not local) will also set
the -g flag; hence parameters exported to the environment will
not be made local to the enclosing function, unless they were
already or the flag +g is given explicitly. If the option is
unset, exported parameters will be made local in just the same way
as any other parameter.
This option is set by default for backward compatibility; it is not
recommended that its behaviour be relied upon. Note that the
builtin export always sets both the -x and -g flags, and hence its
effect extends beyond the scope of the enclosing function; this is
the most portable way to achieve this behaviour.
GLOBAL_RCS (-d) <D>
If this option is unset, the startup files /etc/zprofile,
/etc/zshrc, /etc/zlogin and /etc/zlogout will not be run. It can
be disabled and re-enabled at any time, including inside local
startup files (.zshrc, etc.).
RCS (+f) <D>
After /etc/zshenv is sourced on startup, source the .zshenv,
/etc/zprofile, .zprofile, /etc/zshrc, .zshrc, /etc/zlogin,
.zlogin, and .zlogout files, as described in *Note Files::. If
this option is unset, the /etc/zshenv file is still sourced, but
any of the others will not be; it can be set at any time to
prevent the remaining startup files after the currently executing
one from being sourced.
16.2.6 Input/Output
-------------------
ALIASES <D>
Expand aliases.
CLOBBER (+C, ksh: +C) <D>
Allows `>' redirection to truncate existing files, and `>>' to
create files. Otherwise `>!' or `>|' must be used to truncate a
file, and `>>!' or `>>|' to create a file.
CORRECT (-0)
Try to correct the spelling of commands. Note that, when the
HASH_LIST_ALL option is not set or when some directories in the
path are not readable, this may falsely report spelling errors the
first time some commands are used.
The shell variable CORRECT_IGNORE may be set to a pattern to match
words that will never be offered as corrections.
CORRECT_ALL (-O)
Try to correct the spelling of all arguments in a line.
DVORAK
Use the Dvorak keyboard instead of the standard qwerty keyboard as
a basis for examining spelling mistakes for the CORRECT and
CORRECT_ALL options and the spell-word editor command.
FLOW_CONTROL <D>
If this option is unset, output flow control via start/stop
characters (usually assigned to ^S/^Q) is disabled in the shell's
editor.
IGNORE_EOF (-7)
Do not exit on end-of-file. Require the use of exit or logout
instead. However, ten consecutive EOFs will cause the shell to
exit anyway, to avoid the shell hanging if its tty goes away.
Also, if this option is set and the Zsh Line Editor is used,
widgets implemented by shell functions can be bound to EOF
(normally Control-D) without printing the normal warning message.
This works only for normal widgets, not for completion widgets.
INTERACTIVE_COMMENTS (-k) <K> <S>
Allow comments even in interactive shells.
HASH_CMDS <D>
Note the location of each command the first time it is executed.
Subsequent invocations of the same command will use the saved
location, avoiding a path search. If this option is unset, no
path hashing is done at all. However, when CORRECT is set,
commands whose names do not appear in the functions or aliases
hash tables are hashed in order to avoid reporting them as
spelling errors.
HASH_DIRS <D>
Whenever a command name is hashed, hash the directory containing
it, as well as all directories that occur earlier in the path.
Has no effect if neither HASH_CMDS nor CORRECT is set.
MAIL_WARNING (-U)
Print a warning message if a mail file has been accessed since the
shell last checked.
PATH_DIRS (-Q)
Perform a path search even on command names with slashes in them.
Thus if `/usr/local/bin' is in the user's path, and he or she types
`X11/xinit', the command `/usr/local/bin/X11/xinit' will be
executed (assuming it exists). Commands explicitly beginning with
`/', `./' or `../' are not subject to the path search. This also
applies to the `.' builtin.
Note that subdirectories of the current directory are always
searched for executables specified in this form. This takes place
before any search indicated by this option, and regardless of
whether `.' or the current directory appear in the command search
path.
PRINT_EIGHT_BIT
Print eight bit characters literally in completion lists, etc.
This option is not necessary if your system correctly returns the
printability of eight bit characters (see man page ctype(3)).
PRINT_EXIT_VALUE (-1)
Print the exit value of programs with non-zero exit status.
RC_QUOTES
Allow the character sequence `''' to signify a single quote within
singly quoted strings. Note this does not apply in quoted strings
using the format $'...', where a backslashed single quote can be
used.
RM_STAR_SILENT (-H) <K> <S>
Do not query the user before executing `rm *' or `rm path/*'.
RM_STAR_WAIT
If querying the user before executing `rm *' or `rm path/*', first
wait ten seconds and ignore anything typed in that time. This
avoids the problem of reflexively answering `yes' to the query
when one didn't really mean it. The wait and query can always be
avoided by expanding the `*' in ZLE (with tab).
SHORT_LOOPS <C> <Z>
Allow the short forms of for, repeat, select, if, and function
constructs.
SUN_KEYBOARD_HACK (-L)
If a line ends with a backquote, and there are an odd number of
backquotes on the line, ignore the trailing backquote. This is
useful on some keyboards where the return key is too small, and
the backquote key lies annoyingly close to it.
16.2.7 Job Control
------------------
AUTO_CONTINUE
With this option set, stopped jobs that are removed from the job
table with the disown builtin command are automatically sent a CONT
signal to make them running.
AUTO_RESUME (-W)
Treat single word simple commands without redirection as
candidates for resumption of an existing job.
BG_NICE (-6) <C> <Z>
Run all background jobs at a lower priority. This option is set
by default.
CHECK_JOBS <Z>
Report the status of background and suspended jobs before exiting
a shell with job control; a second attempt to exit the shell will
succeed. NO_CHECK_JOBS is best used only in combination with
NO_HUP, else such jobs will be killed automatically.
The check is omitted if the commands run from the previous command
line included a `jobs' command, since it is assumed the user is
aware that there are background or suspended jobs. A `jobs'
command run from one of the hook functions defined in the section
Special Functions in *Note Functions:: is not counted for this
purpose.
HUP <Z>
Send the HUP signal to running jobs when the shell exits.
LONG_LIST_JOBS (-R)
List jobs in the long format by default.
MONITOR (-m, ksh: -m)
Allow job control. Set by default in interactive shells.
NOTIFY (-5, ksh: -b) <Z>
Report the status of background jobs immediately, rather than
waiting until just before printing a prompt.
16.2.8 Prompting
----------------
PROMPT_BANG <K>
If set, `!' is treated specially in prompt expansion. See *Note
Prompt Expansion::.
PROMPT_CR (+V) <D>
Print a carriage return just before printing a prompt in the line
editor. This is on by default as multi-line editing is only
possible if the editor knows where the start of the line appears.
PROMPT_SP <D>
Attempt to preserve a partial line (i.e. a line that did not end
with a newline) that would otherwise be covered up by the command
prompt due to the PROMPT_CR option. This works by outputting some
cursor-control characters, including a series of spaces, that
should make the terminal wrap to the next line when a partial line
is present (note that this is only successful if your terminal has
automatic margins, which is typical).
When a partial line is preserved, by default you will see an
inverse+bold character at the end of the partial line: a "%" for
a normal user or a "#" for root. If set, the shell parameter
PROMPT_EOL_MARK can be used to customize how the end of partial
lines are shown.
NOTE: if the PROMPT_CR option is not set, enabling this option will
have no effect. This option is on by default.
PROMPT_PERCENT <C> <Z>
If set, `%' is treated specially in prompt expansion. See *Note
Prompt Expansion::.
PROMPT_SUBST <K> <S>
If set, _parameter expansion_, _command substitution_ and
_arithmetic expansion_ are performed in prompts. Substitutions
within prompts do not affect the command status.
TRANSIENT_RPROMPT
Remove any right prompt from display when accepting a command
line. This may be useful with terminals with other cut/paste
methods.
16.2.9 Scripts and Functions
----------------------------
C_BASES
Output hexadecimal numbers in the standard C format, for example
`0xFF' instead of the usual `16#FF'. If the option OCTAL_ZEROES
is also set (it is not by default), octal numbers will be treated
similarly and hence appear as `077' instead of `8#77'. This
option has no effect on the choice of the output base, nor on the
output of bases other than hexadecimal and octal. Note that these
formats will be understood on input irrespective of the setting of
C_BASES.
C_PRECEDENCES
This alters the precedence of arithmetic operators to be more like
C and other programming languages; Arithmetic Evaluation has an
explicit list.
DEBUG_BEFORE_CMD
Run the DEBUG trap before each command; otherwise it is run after
each command. Setting this option mimics the behaviour of ksh 93;
with the option unset the behaviour is that of ksh 88.
ERR_EXIT (-e, ksh: -e)
If a command has a non-zero exit status, execute the ZERR trap, if
set, and exit. This is disabled while running initialization
scripts.
The behaviour is also disabled inside DEBUG traps. In this case
the option is handled specially: it is unset on entry to the trap.
If the option DEBUG_BEFORE_CMD is set, as it is by default, and
the option ERR_EXIT is found to have been set on exit, then the
command for which the DEBUG trap is being executed is skipped.
The option is restored after the trap exits.
ERR_RETURN
If a command has a non-zero exit status, return immediately from
the enclosing function. The logic is identical to that for
ERR_EXIT, except that an implicit return statement is executed
instead of an exit. This will trigger an exit at the outermost
level of a non-interactive script.
EVAL_LINENO <Z>
If set, line numbers of expressions evaluated using the builtin
eval are tracked separately of the enclosing environment. This
applies both to the parameter LINENO and the line number output by
the prompt escape %i. If the option is set, the prompt escape %N
will output the string `(eval)' instead of the script or function
name as an indication. (The two prompt escapes are typically
used in the parameter PS4 to be output when the option XTRACE is
set.) If EVAL_LINENO is unset, the line number of the surrounding
script or function is retained during the evaluation.
EXEC (+n, ksh: +n) <D>
Do execute commands. Without this option, commands are read and
checked for syntax errors, but not executed. This option cannot
be turned off in an interactive shell, except when `-n' is
supplied to the shell at startup.
FUNCTION_ARGZERO <C> <Z>
When executing a shell function or sourcing a script, set $0
temporarily to the name of the function/script.
LOCAL_OPTIONS <K>
If this option is set at the point of return from a shell function,
most options (including this one) which were in force upon entry to
the function are restored; options that are not restored are
PRIVILEGED and RESTRICTED. Otherwise, only this option and the
XTRACE and PRINT_EXIT_VALUE options are restored. Hence if this
is explicitly unset by a shell function the other options in force
at the point of return will remain so. A shell function can also
guarantee itself a known shell configuration with a formulation
like `emulate -L zsh'; the -L activates LOCAL_OPTIONS.
LOCAL_TRAPS <K>
If this option is set when a signal trap is set inside a function,
then the previous status of the trap for that signal will be
restored when the function exits. Note that this option must be
set _prior_ to altering the trap behaviour in a function; unlike
LOCAL_OPTIONS, the value on exit from the function is irrelevant.
However, it does not need to be set before any global trap for
that to be correctly restored by a function. For example,
unsetopt localtraps
trap - INT
fn() { setopt localtraps; trap '' INT; sleep 3; }
will restore normally handling of SIGINT after the function exits.
MULTI_FUNC_DEF <Z>
Allow definitions of multiple functions at once in the form `fn1
fn2...()'; if the option is not set, this causes a parse error.
Definition of multiple functions with the function keyword is
always allowed. Multiple function definitions are not often used
and can cause obscure errors.
MULTIOS <Z>
Perform implicit `tee's or `cat's when multiple redirections are
attempted (see *Note Redirection::).
OCTAL_ZEROES <S>
Interpret any integer constant beginning with a 0 as octal, per
IEEE Std 1003.2-1992 (ISO 9945-2:1993). This is not enabled by
default as it causes problems with parsing of, for example, date
and time strings with leading zeroes.
Sequences of digits indicating a numeric base such as the `08'
component in `08#77' are always interpreted as decimal, regardless
of leading zeroes.
TYPESET_SILENT
If this is unset, executing any of the `typeset' family of
commands with no options and a list of parameters that have no
values to be assigned but already exist will display the value of
the parameter. If the option is set, they will only be shown when
parameters are selected with the `-m' option. The option `-p' is
available whether or not the option is set.
VERBOSE (-v, ksh: -v)
Print shell input lines as they are read.
XTRACE (-x, ksh: -x)
Print commands and their arguments as they are executed.
16.2.10 Shell Emulation
-----------------------
BASH_REMATCH
When set, matches performed with the =~ operator will set the
BASH_REMATCH array variable, instead of the default MATCH and
match variables. The first element of the BASH_REMATCH array will
contain the entire matched text and subsequent elements will
contain extracted substrings. This option makes more sense when
KSH_ARRAYS is also set, so that the entire matched portion is
stored at index 0 and the first substring is at index 1. Without
this option, the MATCH variable contains the entire matched text
and the match array variable contains substrings.
BSD_ECHO <S>
Make the echo builtin compatible with the BSD man page echo(1)
command. This disables backslashed escape sequences in echo
strings unless the -e option is specified.
CSH_JUNKIE_HISTORY <C>
A history reference without an event specifier will always refer
to the previous command. Without this option, such a history
reference refers to the same event as the previous history
reference, defaulting to the previous command.
CSH_JUNKIE_LOOPS <C>
Allow loop bodies to take the form `LIST; end' instead of `do
LIST; done'.
CSH_JUNKIE_QUOTES <C>
Changes the rules for single- and double-quoted text to match that
of `csh'. These require that embedded newlines be preceded by a
backslash; unescaped newlines will cause an error message. In
double-quoted strings, it is made impossible to escape `$', ``' or
`"' (and `\' itself no longer needs escaping). Command
substitutions are only expanded once, and cannot be nested.
CSH_NULLCMD <C>
Do not use the values of NULLCMD and READNULLCMD when running
redirections with no command. This make such redirections fail
(see *Note Redirection::).
KSH_ARRAYS <K> <S>
Emulate `ksh' array handling as closely as possible. If this
option is set, array elements are numbered from zero, an array
parameter without subscript refers to the first element instead of
the whole array, and braces are required to delimit a subscript
(`${path[2]}' rather than just `$path[2]').
KSH_AUTOLOAD <K> <S>
Emulate `ksh' function autoloading. This means that when a
function is autoloaded, the corresponding file is merely executed,
and must define the function itself. (By default, the function is
defined to the contents of the file. However, the most common
`ksh'-style case - of the file containing only a simple definition
of the function - is always handled in the `ksh'-compatible
manner.)
KSH_OPTION_PRINT <K>
Alters the way options settings are printed: instead of separate
lists of set and unset options, all options are shown, marked `on'
if they are in the non-default state, `off' otherwise.
KSH_TYPESET <K>
Alters the way arguments to the typeset family of commands,
including declare, export, float, integer, local and readonly, are
processed. Without this option, zsh will perform normal word
splitting after command and parameter expansion in arguments of an
assignment; with it, word splitting does not take place in those
cases.
KSH_ZERO_SUBSCRIPT
Treat use of a subscript of value zero in array or string
expressions as a reference to the first element, i.e. the element
that usually has the subscript 1. Ignored if KSH_ARRAYS is also
set.
If neither this option nor KSH_ARRAYS is set, accesses to an
element of an array or string with subscript zero return an empty
element or string, while attempts to set element zero of an array
or string are treated as an error. However, attempts to set an
otherwise valid subscript range that includes zero will succeed.
For example, if KSH_ZERO_SUBSCRIPT is not set,
array[0]=(element)
is an error, while
array[0,1]=(element)
is not and will replace the first element of the array.
This option is for compatibility with older versions of the shell
and is not recommended in new code.
POSIX_ALIASES <K> <S>
When this option is set, reserved words are not candidates for
alias expansion: it is still possible to declare any of them as
an alias, but the alias will never be expanded. Reserved words
are described in *Note Reserved Words::.
Alias expansion takes place while text is being read; hence when
this option is set it does not take effect until the end of any
function or other piece of shell code parsed as one unit. Note
this may cause differences from other shells even when the option
is in effect. For example, when running a command with `zsh -c',
or even `zsh -o posixaliases -c', the entire command argument is
parsed as one unit, so aliases defined within the argument are not
available even in later lines. If in doubt, avoid use of aliases
in non-interactive code.
POSIX_BUILTINS <K> <S>
When this option is set the command builtin can be used to execute
shell builtin commands. Parameter assignments specified before
shell functions and special builtins are kept after the command
completes unless the special builtin is prefixed with the command
builtin. Special builtins are ., :, break, continue, declare,
eval, exit, export, integer, local, readonly, return, set, shift,
source, times, trap and unset.
POSIX_IDENTIFIERS <K> <S>
When this option is set, only the ASCII characters a to z, A to Z,
0 to 9 and _ may be used in identifiers (names of shell parameters
and modules).
When the option is unset and multibyte character support is
enabled (i.e. it is compiled in and the option MULTIBYTE is set),
then additionally any alphanumeric characters in the local
character set may be used in identifiers. Note that scripts and
functions written with this feature are not portable, and also
that both options must be set before the script or function is
parsed; setting them during execution is not sufficient as the
syntax VARIABLE=VALUE has already been parsed as a command rather
than an assignment.
If multibyte character support is not compiled into the shell this
option is ignored; all octets with the top bit set may be used in
identifiers. This is non-standard but is the traditional zsh
behaviour.
SH_FILE_EXPANSION <K> <S>
Perform filename expansion (e.g., ~ expansion) _before_ parameter
expansion, command substitution, arithmetic expansion and brace
expansion. If this option is unset, it is performed _after_ brace
expansion, so things like `~$USERNAME' and `~{pfalstad,rc}' will
work.
SH_NULLCMD <K> <S>
Do not use the values of NULLCMD and READNULLCMD when doing
redirections, use `:' instead (see *Note Redirection::).
SH_OPTION_LETTERS <K> <S>
If this option is set the shell tries to interpret single letter
options (which are used with set and setopt) like `ksh' does.
This also affects the value of the - special parameter.
SH_WORD_SPLIT (-y) <K> <S>
Causes field splitting to be performed on unquoted parameter
expansions. Note that this option has nothing to do with word
splitting. (See *Note Parameter Expansion::.)
TRAPS_ASYNC
While waiting for a program to exit, handle signals and run traps
immediately. Otherwise the trap is run after a child process has
exited. Note this does not affect the point at which traps are
run for any case other than when the shell is waiting for a child
process.
16.2.11 Shell State
-------------------
INTERACTIVE (-i, ksh: -i)
This is an interactive shell. This option is set upon
initialisation if the standard input is a tty and commands are
being read from standard input. (See the discussion of
SHIN_STDIN.) This heuristic may be overridden by specifying a
state for this option on the command line. The value of this
option can only be changed via flags supplied at invocation of the
shell. It cannot be changed once zsh is running.
LOGIN (-l, ksh: -l)
This is a login shell. If this option is not explicitly set, the
shell is a login shell if the first character of the argv[0]
passed to the shell is a `-'.
PRIVILEGED (-p, ksh: -p)
Turn on privileged mode. This is enabled automatically on startup
if the effective user (group) ID is not equal to the real user
(group) ID. Turning this option off causes the effective user and
group IDs to be set to the real user and group IDs. This option
disables sourcing user startup files. If zsh is invoked as `sh'
or `ksh' with this option set, /etc/suid_profile is sourced (after
/etc/profile on interactive shells). Sourcing ~/.profile is
disabled and the contents of the ENV variable is ignored. This
option cannot be changed using the -m option of setopt and
unsetopt, and changing it inside a function always changes it
globally regardless of the LOCAL_OPTIONS option.
RESTRICTED (-r)
Enables restricted mode. This option cannot be changed using
unsetopt, and setting it inside a function always changes it
globally regardless of the LOCAL_OPTIONS option. See *Note
Restricted Shell::.
SHIN_STDIN (-s, ksh: -s)
Commands are being read from the standard input. Commands are
read from standard input if no command is specified with -c and no
file of commands is specified. If SHIN_STDIN is set explicitly on
the command line, any argument that would otherwise have been
taken as a file to run will instead be treated as a normal
positional parameter. Note that setting or unsetting this option
on the command line does not necessarily affect the state the
option will have while the shell is running - that is purely an
indicator of whether on not commands are _actually_ being read
from standard input. The value of this option can only be changed
via flags supplied at invocation of the shell. It cannot be
changed once zsh is running.
SINGLE_COMMAND (-t, ksh: -t)
If the shell is reading from standard input, it exits after a
single command has been executed. This also makes the shell
non-interactive, unless the INTERACTIVE option is explicitly set
on the command line. The value of this option can only be changed
via flags supplied at invocation of the shell. It cannot be
changed once zsh is running.
16.2.12 Zle
-----------
BEEP (+B) <D>
Beep on error in ZLE.
COMBINING_CHARS
Assume that the terminal displays combining characters correctly.
Specifically, if a base alphanumeric character is followed by one
or more zero-width punctuation characters, assume that the
zero-width characters will be displayed as modifications to the
base character within the same width. Not all terminals handle
this. If this option is not set, zero-width characters are
displayed separately with special mark-up.
If this option is set, the pattern test [[:WORD:]] matches a
zero-width punctuation character on the assumption that it will be
used as part of a word in combination with a word character.
Otherwise the base shell does not handle combining characters
specially.
EMACS
If ZLE is loaded, turning on this option has the equivalent effect
of `bindkey -e'. In addition, the VI option is unset. Turning it
off has no effect. The option setting is not guaranteed to
reflect the current keymap. This option is provided for
compatibility; bindkey is the recommended interface.
OVERSTRIKE
Start up the line editor in overstrike mode.
SINGLE_LINE_ZLE (-M) <K>
Use single-line command line editing instead of multi-line.
Note that although this is on by default in ksh emulation it only
provides superficial compatibility with the ksh line editor and
reduces the effectiveness of the zsh line editor. As it has no
effect on shell syntax, many users may wish to disable this option
when using ksh emulation interactively.
VI
If ZLE is loaded, turning on this option has the equivalent effect
of `bindkey -v'. In addition, the EMACS option is unset. Turning
it off has no effect. The option setting is not guaranteed to
reflect the current keymap. This option is provided for
compatibility; bindkey is the recommended interface.
ZLE (-Z)
Use the zsh line editor. Set by default in interactive shells
connected to a terminal.
File: zsh.info, Node: Option Aliases, Next: Single Letter Options, Prev: Description of Options, Up: Options
16.3 Option Aliases
===================
Some options have alternative names. These aliases are never used for
output, but can be used just like normal option names when specifying
options to the shell.
BRACE_EXPAND
_NO__IGNORE_BRACES (ksh and bash compatibility)
DOT_GLOB
GLOB_DOTS (bash compatibility)
HASH_ALL
HASH_CMDS (bash compatibility)
HIST_APPEND
APPEND_HISTORY (bash compatibility)
HIST_EXPAND
BANG_HIST (bash compatibility)
LOG
_NO__HIST_NO_FUNCTIONS (ksh compatibility)
MAIL_WARN
MAIL_WARNING (bash compatibility)
ONE_CMD
SINGLE_COMMAND (bash compatibility)
PHYSICAL
CHASE_LINKS (ksh and bash compatibility)
PROMPT_VARS
PROMPT_SUBST (bash compatibility)
STDIN
SHIN_STDIN (ksh compatibility)
TRACK_ALL
HASH_CMDS (ksh compatibility)
File: zsh.info, Node: Single Letter Options, Prev: Option Aliases, Up: Options
16.4 Single Letter Options
==========================
16.4.1 Default set
------------------
-0
CORRECT
-1
PRINT_EXIT_VALUE
-2
_NO__BAD_PATTERN
-3
_NO__NOMATCH
-4
GLOB_DOTS
-5
NOTIFY
-6
BG_NICE
-7
IGNORE_EOF
-8
MARK_DIRS
-9
AUTO_LIST
-B
_NO__BEEP
-C
_NO__CLOBBER
-D
PUSHD_TO_HOME
-E
PUSHD_SILENT
-F
_NO__GLOB
-G
NULL_GLOB
-H
RM_STAR_SILENT
-I
IGNORE_BRACES
-J
AUTO_CD
-K
_NO__BANG_HIST
-L
SUN_KEYBOARD_HACK
-M
SINGLE_LINE_ZLE
-N
AUTO_PUSHD
-O
CORRECT_ALL
-P
RC_EXPAND_PARAM
-Q
PATH_DIRS
-R
LONG_LIST_JOBS
-S
REC_EXACT
-T
CDABLE_VARS
-U
MAIL_WARNING
-V
_NO__PROMPT_CR
-W
AUTO_RESUME
-X
LIST_TYPES
-Y
MENU_COMPLETE
-Z
ZLE
-a
ALL_EXPORT
-e
ERR_EXIT
-f
_NO__RCS
-g
HIST_IGNORE_SPACE
-h
HIST_IGNORE_DUPS
-i
INTERACTIVE
-k
INTERACTIVE_COMMENTS
-l
LOGIN
-m
MONITOR
-n
_NO__EXEC
-p
PRIVILEGED
-r
RESTRICTED
-s
SHIN_STDIN
-t
SINGLE_COMMAND
-u
_NO__UNSET
-v
VERBOSE
-w
CHASE_LINKS
-x
XTRACE
-y
SH_WORD_SPLIT
16.4.2 sh/ksh emulation set
---------------------------
-C
_NO__CLOBBER
-T
TRAPS_ASYNC
-X
MARK_DIRS
-a
ALL_EXPORT
-b
NOTIFY
-e
ERR_EXIT
-f
_NO__GLOB
-i
INTERACTIVE
-l
LOGIN
-m
MONITOR
-n
_NO__EXEC
-p
PRIVILEGED
-r
RESTRICTED
-s
SHIN_STDIN
-t
SINGLE_COMMAND
-u
_NO__UNSET
-v
VERBOSE
-x
XTRACE
16.4.3 Also note
----------------
-A
Used by set for setting arrays
-b
Used on the command line to specify end of option processing
-c
Used on the command line to specify a single command
-m
Used by setopt for pattern-matching option setting
-o
Used in all places to allow use of long option names
-s
Used by set to sort positional parameters
File: zsh.info, Node: Shell Builtin Commands, Next: Zsh Line Editor, Prev: Options, Up: Top
17 Shell Builtin Commands
*************************
- SIMPLE COMMAND
See *Note Precommand Modifiers::.
. FILE [ ARG ... ]
Read commands from FILE and execute them in the current shell
environment.
If FILE does not contain a slash, or if PATH_DIRS is set, the
shell looks in the components of $path to find the directory
containing FILE. Files in the current directory are not read
unless `.' appears somewhere in $path. If a file named `FILE.zwc'
is found, is newer than FILE, and is the compiled form (created
with the zcompile builtin) of FILE, then commands are read from
that file instead of FILE.
If any arguments ARG are given, they become the positional
parameters; the old positional parameters are restored when the
FILE is done executing. The exit status is the exit status of the
last command executed.
: [ ARG ... ]
This command does nothing, although normal argument expansions is
performed which may have effects on shell parameters. A zero exit
status is returned.
alias [ {+|-}gmrsL ] [ NAME[=VALUE] ... ]
For each NAME with a corresponding VALUE, define an alias with
that value. A trailing space in VALUE causes the next word to be
checked for alias expansion. If the -g flag is present, define a
global alias; global aliases are expanded even if they do not
occur in command position.
If the -s flags is present, define a suffix alias: if the command
word on a command line is in the form `TEXT.NAME', where TEXT is
any non-empty string, it is replaced by the text `VALUE
TEXT.NAME'. Note that NAME is treated as a literal string, not a
pattern. A trailing space in VALUE is not special in this case.
For example,
alias -s ps=gv
will cause the command `*.ps' to be expanded to `gv *.ps'. As
alias expansion is carried out earlier than globbing, the `*.ps'
will then be expanded. Suffix aliases constitute a different name
space from other aliases (so in the above example it is still
possible to create an alias for the command ps) and the two sets
are never listed together.
For each NAME with no VALUE, print the value of NAME, if any.
With no arguments, print all currently defined aliases other than
suffix aliases. If the -m flag is given the arguments are taken
as patterns (they should be quoted to preserve them from being
interpreted as glob patterns), and the aliases matching these
patterns are printed. When printing aliases and one of the -g, -r
or -s flags is present, restrict the printing to global, regular
or suffix aliases, respectively; a regular alias is one which is
neither a global nor a suffix alias. Using `+' instead of `-',
or ending the option list with a single `+', prevents the values
of the aliases from being printed.
If the -L flag is present, then print each alias in a manner
suitable for putting in a startup script. The exit status is
nonzero if a NAME (with no VALUE) is given for which no alias has
been defined.
For more on aliases, include common problems, *Note Aliasing::.
autoload [ {+|-}UXktz ] [ -w ] [ NAME ... ]
Equivalent to functions -u, with the exception of -X/+X and -w.
The flag -X may be used only inside a shell function, and may not
be followed by a NAME. It causes the calling function to be
marked for autoloading and then immediately loaded and executed,
with the current array of positional parameters as arguments.
This replaces the previous definition of the function. If no
function definition is found, an error is printed and the function
remains undefined and marked for autoloading.
The flag +X attempts to load each NAME as an autoloaded function,
but does _not_ execute it. The exit status is zero (success) if
the function was not previously defined _and_ a definition for it
was found. This does _not_ replace any existing definition of the
function. The exit status is nonzero (failure) if the function
was already defined or when no definition was found. In the
latter case the function remains undefined and marked for
autoloading. If ksh-style autoloading is enabled, the function
created will contain the contents of the file plus a call to the
function itself appended to it, thus giving normal ksh autoloading
behaviour on the first call to the function.
With the -w flag, the NAMEs are taken as names of files compiled
with the zcompile builtin, and all functions defined in them are
marked for autoloading.
The flags -z and -k mark the function to be autoloaded in native
or ksh emulation, as if the option KSH_AUTOLOAD were unset or were
set, respectively. The flags override the setting of the option
at the time the function is loaded.
bg [ JOB ... ]
JOB ... &
Put each specified JOB in the background, or the current job if
none is specified.
bindkey
See *Note Zle Builtins::.
break [ N ]
Exit from an enclosing for, while, until, select or repeat loop.
If N is specified, then break N levels instead of just one.
builtin NAME [ ARGS ... ]
Executes the builtin NAME, with the given ARGS.
bye
Same as exit.
cap
See *Note The zsh/cap Module::.
cd [ -qsLP ] [ ARG ]
cd [ -qsLP ] OLD NEW
cd [ -qsLP ] {+|-}N
Change the current directory. In the first form, change the
current directory to ARG, or to the value of $HOME if ARG is not
specified. If ARG is `-', change to the value of $OLDPWD, the
previous directory.
Otherwise, if ARG begins with a slash, attempt to change to the
directory given by ARG.
If ARG does not begin with a slash, the behaviour depends on
whether the current directory `.' occurs in the list of
directories contained in the shell parameter cdpath. If it does
not, first attempt to change to the directory ARG under the
current directory, and if that fails but cdpath is set and
contains at least one element attempt to change to the directory
ARG under each component of cdpath in turn until successful. If
`.' occurs in cdpath, then cdpath is searched strictly in order so
that `.' is only tried at the appropriate point.
If no directory is found, the option CDABLE_VARS is set, and a
parameter named ARG exists whose value begins with a slash, treat
its value as the directory. In that case, the parameter is added
to the named directory hash table.
The second form of cd substitutes the string NEW for the string
OLD in the name of the current directory, and tries to change to
this new directory.
The third form of cd extracts an entry from the directory stack,
and changes to that directory. An argument of the form `+N'
identifies a stack entry by counting from the left of the list
shown by the dirs command, starting with zero. An argument of the
form `-N' counts from the right. If the PUSHD_MINUS option is
set, the meanings of `+' and `-' in this context are swapped.
If the -q (quiet) option is specified, the hook function chpwd and
the functions in the array chpwd_functions are not called. This
is useful for calls to cd that do not change the environment seen
by an interactive user.
If the -s option is specified, cd refuses to change the current
directory if the given pathname contains symlinks. If the -P
option is given or the CHASE_LINKS option is set, symbolic links
are resolved to their true values. If the -L option is given
symbolic links are retained in the directory (and not resolved)
regardless of the state of the CHASE_LINKS option.
chdir
Same as cd.
clone
See *Note The zsh/clone Module::.
command [ -pvV ] SIMPLE COMMAND
The simple command argument is taken as an external command
instead of a function or builtin and is executed. If the
POSIX_BUILTINS option is set, builtins will also be executed but
certain special properties of them are suppressed. The -p flag
causes a default path to be searched instead of that in $path.
With the -v flag, command is similar to whence and with -V, it is
equivalent to whence -v.
See also *Note Precommand Modifiers::.
comparguments
See *Note The zsh/computil Module::.
compcall
See *Note The zsh/compctl Module::.
compctl
See *Note The zsh/compctl Module::.
compdescribe
See *Note The zsh/computil Module::.
compfiles
See *Note The zsh/computil Module::.
compgroups
See *Note The zsh/computil Module::.
compquote
See *Note The zsh/computil Module::.
comptags
See *Note The zsh/computil Module::.
comptry
See *Note The zsh/computil Module::.
compvalues
See *Note The zsh/computil Module::.
continue [ N ]
Resume the next iteration of the enclosing for, while, until,
select or repeat loop. If N is specified, break out of N-1 loops
and resume at the Nth enclosing loop.
declare
Same as typeset.
dirs [ -c ] [ ARG ... ]
dirs [ -lpv ]
With no arguments, print the contents of the directory stack.
Directories are added to this stack with the pushd command, and
removed with the cd or popd commands. If arguments are specified,
load them onto the directory stack, replacing anything that was
there, and push the current directory onto the stack.
-c
clear the directory stack.
-l
print directory names in full instead of using of using ~
expressions.
-p
print directory entries one per line.
-v
number the directories in the stack when printing.
disable [ -afmrs ] NAME ...
Temporarily disable the NAMEd hash table elements. The default is
to disable builtin commands. This allows you to use an external
command with the same name as a builtin command. The -a option
causes disable to act on regular or global aliases. The -s option
causes disable to act on suffix aliases. The -f option causes
disable to act on shell functions. The -r options causes disable
to act on reserved words. Without arguments all disabled hash
table elements from the corresponding hash table are printed.
With the -m flag the arguments are taken as patterns (which should
be quoted to prevent them from undergoing filename expansion), and
all hash table elements from the corresponding hash table matching
these patterns are disabled. Disabled objects can be enabled with
the enable command.
disown [ JOB ... ]
JOB ... &|
JOB ... &!
Remove the specified JOBs from the job table; the shell will no
longer report their status, and will not complain if you try to
exit an interactive shell with them running or stopped. If no JOB
is specified, disown the current job.
If the JOBs are currently stopped and the AUTO_CONTINUE option is
not set, a warning is printed containing information about how to
make them running after they have been disowned. If one of the
latter two forms is used, the JOBs will automatically be made
running, independent of the setting of the AUTO_CONTINUE option.
echo [ -neE ] [ ARG ... ]
Write each ARG on the standard output, with a space separating
each one. If the -n flag is not present, print a newline at the
end. echo recognizes the following escape sequences:
\a
bell character
\b
backspace
\c
suppress final newline
\e
escape
\f
form feed
\n
linefeed (newline)
\r
carriage return
\t
horizontal tab
\v
vertical tab
\\
backslash
\0NNN
character code in octal
\xNN
character code in hexadecimal
\uNNNN
unicode character code in hexadecimal
\UNNNNNNNN
unicode character code in hexadecimal
The -E flag, or the BSD_ECHO option, can be used to disable these
escape sequences. In the latter case, -e flag can be used to
enable them.
echotc
See *Note The zsh/termcap Module::.
echoti
See *Note The zsh/terminfo Module::.
emulate [ -LR ] [ {zsh|sh|ksh|csh} [ -c arg ] ]
Without any argument print current emulation mode.
With single argument set up zsh options to emulate the specified
shell as much as possible. `csh' will never be fully emulated.
If the argument is not one of the shells listed above, zsh will be
used as a default; more precisely, the tests performed on the
argument are the same as those used to determine the emulation at
startup based on the shell name, see *Note Compatibility:: .
If the -R option is given, all options are reset to their default
value corresponding to the specified emulation mode, except for
certain options describing the interactive environment; otherwise,
only those options likely to cause portability problems in scripts
and functions are altered. If the -L option is given, the options
LOCAL_OPTIONS and LOCAL_TRAPS will be set as well, causing the
effects of the emulate command and any setopt and trap commands to
be local to the immediately surrounding shell function, if any;
normally these options are turned off in all emulation modes
except ksh. The -L and -c are mutually exclusive.
If -c arg is given, evaluate arg while the requested emulation is
temporarily in effect. The emulation and all options will be
restored to their original values before emulate returns. The -R
flag may be used.
Use of -c enables `sticky' emulation mode for functions defined
within the evaluated expression: the emulation mode is associated
thereafter with the function so that whenever the function is
executed the emulation (respecting the -R flag, if present) and all
options are set before entry to the function, and restored after
exit. If the function is called when the sticky emulation is
already in effect, either within an `emulate SHELL -c' expression
or within another function with the same sticky emulation, entry
and exit from the function do not cause options to be altered
(except due to standard processing such as the LOCAL_OPTIONS
option).
For example:
emulate sh -c 'fni() { setopt cshnullglob; }
fno() { fni; }'
fno
The two functions fni and fno are defined with sticky sh
emulation. fno is then executed, causing options associated with
emulations to be set to their values in sh. fni then calls fno;
because fno is also marked for sticky sh emulation, no option
changes take place on entry to or exit from it. Hence the option
cshnullglob, turned off by sh emulation, will be turned on within
fni and remain on on return to fno. On exit from fno, the
emulation mode and all options will be restored to the state they
were in before entry to the temporary emulation.
The documentation above is typically sufficient for the intended
purpose of executing code designed for other shells in a suitable
environment. More detailed rules follow.
1.
The sticky emulation environment provided by `emulate SHELL
-c' is identical to that provided by entry to a function
marked for sticky emulation as a consequence of being defined
in such an environment. Hence, for example, the sticky
emulation is inherited by subfunctions defined within
functions with sticky emulation.
2.
No change of options takes place on entry to or exit from
functions that are not marked for sticky emulation, other
than those that would normally take place, even if those
functions are called within sticky emulation.
3.
No special handling is provided for functions marked for
autoload nor for functions present in wordcode created by the
zcompile command.
4.
The presence or absence of the -R flag to emulate corresponds
to different sticky emulation modes, so for example `emulate
sh -c', `emulate -R sh -c' and `emulate csh -c' are treated
as three distinct sticky emulations.
enable [ -afmrs ] NAME ...
Enable the NAMEd hash table elements, presumably disabled earlier
with disable. The default is to enable builtin commands. The -a
option causes enable to act on regular or global aliases. The -s
option causes enable to act on suffix aliases. The -f option
causes enable to act on shell functions. The -r option causes
enable to act on reserved words. Without arguments all enabled
hash table elements from the corresponding hash table are printed.
With the -m flag the arguments are taken as patterns (should be
quoted) and all hash table elements from the corresponding hash
table matching these patterns are enabled. Enabled objects can be
disabled with the disable builtin command.
eval [ ARG ... ]
Read the arguments as input to the shell and execute the resulting
command(s) in the current shell process. The return status is the
same as if the commands had been executed directly by the shell;
if there are no ARGS or they contain no commands (i.e. are an
empty string or whitespace) the return status is zero.
exec [ -cl ] [ -a ARGV0 ] SIMPLE COMMAND
Replace the current shell with an external command rather than
forking. With -c clear the environment; with -l prepend - to the
argv[0] string of the command executed (to simulate a login shell);
with -a ARGV0 set the argv[0] string of the command executed. See
*Note Precommand Modifiers::.
exit [ N ]
Exit the shell with the exit status specified by N; if none is
specified, use the exit status from the last command executed. An
EOF condition will also cause the shell to exit, unless the
IGNORE_EOF option is set.
export [ NAME[=VALUE] ... ]
The specified NAMEs are marked for automatic export to the
environment of subsequently executed commands. Equivalent to
typeset -gx. If a parameter specified does not already exist, it
is created in the global scope.
false [ ARG ... ]
Do nothing and return an exit status of 1.
fc [ -e ENAME ] [ -m MATCH ] [ OLD=NEW ... ] [ FIRST [ LAST ] ]
fc -l [ -nrdfEiD ] [ -t TIMEFMT ] [ -m MATCH ]
[ OLD=NEW ... ] [ FIRST [ LAST ] ]
fc -p [ -a ] [ FILENAME [ HISTSIZE [ SAVEHISTSIZE ] ] ]
fc -P
fc -ARWI [ FILENAME ]
Select a range of commands from FIRST to LAST from the history
list. The arguments FIRST and LAST may be specified as a number
or as a string. A negative number is used as an offset to the
current history event number. A string specifies the most recent
event beginning with the given string. All substitutions OLD=NEW,
if any, are then performed on the commands.
If the -l flag is given, the resulting commands are listed on
standard output. If the -m flag is also given the first argument
is taken as a pattern (should be quoted) and only the history
events matching this pattern will be shown. Otherwise the editor
program ENAME is invoked on a file containing these history
events. If ENAME is not given, the value of the parameter FCEDIT
is used; if that is not set the value of the parameter EDITOR is
used; if that is not set a builtin default, usually `vi' is used.
If ENAME is `-', no editor is invoked. When editing is complete,
the edited command is executed.
If FIRST is not specified, it will be set to -1 (the most recent
event), or to -16 if the -l flag is given. If LAST is not
specified, it will be set to FIRST, or to -1 if the -l flag is
given.
The flag -r reverses the order of the commands and the flag -n
suppresses command numbers when listing.
Also when listing,
-d
prints timestamps for each command
-f
prints full time-date stamps in the US `MM/DD/YY HH:MM' format
-E
prints full time-date stamps in the European `DD.MM.YYYY
HH:MM' format
-i
prints full time-date stamps in ISO8601 `YYYY-MM-DD HH:MM'
format
-t FMT
prints time and date stamps in the given format; FMT is
formatted with the strftime function with the zsh extensions
described for the %D{STRING} prompt format in *Note Prompt
Expansion::. The resulting formatted string must be no more
than 256 characters or will not be printed.
-D
prints elapsed times; may be combined with one of the options
above.
`fc -p' pushes the current history list onto a stack and switches
to a new history list. If the -a option is also specified, this
history list will be automatically popped when the current
function scope is exited, which is a much better solution than
creating a trap function to call `fc -P' manually. If no
arguments are specified, the history list is left empty, $HISTFILE
is unset, and $HISTSIZE & $SAVEHIST are set to their default
values. If one argument is given, $HISTFILE is set to that
filename, $HISTSIZE & $SAVEHIST are left unchanged, and the history
file is read in (if it exists) to initialize the new list. If a
second argument is specified, $HISTSIZE & $SAVEHIST are instead
set to the single specified numeric value. Finally, if a third
argument is specified, $SAVEHIST is set to a separate value from
$HISTSIZE. You are free to change these environment values for
the new history list however you desire in order to manipulate the
new history list.
`fc -P' pops the history list back to an older list saved by `fc
-p'. The current list is saved to its $HISTFILE before it is
destroyed (assuming that $HISTFILE and $SAVEHIST are set
appropriately, of course). The values of $HISTFILE, $HISTSIZE,
and $SAVEHIST are restored to the values they had when `fc -p' was
called. Note that this restoration can conflict with making these
variables "local", so your best bet is to avoid local declarations
for these variables in functions that use `fc -p'. The one other
guaranteed-safe combination is declaring these variables to be
local at the top of your function and using the automatic option
(-a) with `fc -p'. Finally, note that it is legal to manually pop
a push marked for automatic popping if you need to do so before the
function exits.
`fc -R' reads the history from the given file, `fc -W' writes the
history out to the given file, and `fc -A' appends the history out
to the given file. If no filename is specified, the $HISTFILE is
assumed. If the -I option is added to -R, only those events that
are not already contained within the internal history list are
added. If the -I option is added to -A or -W, only those events
that are new since last incremental append/write to the history
file are appended/written. In any case, the created file will
have no more than $SAVEHIST entries.
fg [ JOB ... ]
JOB ...
Bring each specified JOB in turn to the foreground. If no JOB is
specified, resume the current job.
float [ {+|-}EFHghlprtux ] [ -LRZ [ N ]] [ NAME[=VALUE] ... ]
Equivalent to typeset -E, except that options irrelevant to
floating point numbers are not permitted.
functions [ {+|-}UXkmtuz ] [ NAME ... ]
functions -M MATHFN [ MIN [ MAX [ SHELLFN ] ] ]
functions -M [ -m PATTERN ... ]
functions +M [ -m ] MATHFN
Equivalent to typeset -f, with the exception of the -M option.
Use of the -M option may not be combined with any of the options
handled by typeset -f.
functions -M MATHFN defines MATHFN as the name of a mathematical
function recognised in all forms of arithmetical expressions; see
*Note Arithmetic Evaluation::. By default MATHFN may take any
number of comma-separated arguments. If MIN is given, it must
have exactly MIN args; if MIN and MAX are both given, it must have
at least MIN and and at most MAX args. MAX may be -1 to indicate
that there is no upper limit.
By default the function is implemented by a shell function of the
same name; if SHELLFN is specified it gives the name of the
corresponding shell function while MATHFN remains the name used in
arithmetical expressions. The name of the function in $0 is
MATHFN (not SHELLFN as would usually be the case), provided the
option FUNCTION_ARGZERO is in effect. The positional parameters
in the shell function correspond to the arguments of the
mathematical function call. The result of the last arithmetical
expression evaluated inside the shell function (even if it is a
form that normally only returns a status) gives the result of the
mathematical function.
functions -M with no arguments lists all such user-defined
functions in the same form as a definition. With the additional
option -m and a list of arguments, all functions whose MATHFN
matches one of the pattern arguments are listed.
function +M removes the list of mathematical functions; with the
additional option -m the arguments are treated as patterns and all
functions whose mathfn matches the pattern are removed. Note that
the shell function implementing the behaviour is not removed
(regardless of whether its name coincides with mathfn).
For example, the following prints the cube of 3:
zmath_cube() { (( $1 * $1 * $1 )) }
functions -M cube 1 1 zmath_cube
print $(( cube(3) ))
getcap
See *Note The zsh/cap Module::.
getln [ -AclneE ] NAME ...
Read the top value from the buffer stack and put it in the shell
parameter name. Equivalent to read -zr.
getopts OPTSTRING NAME [ ARG ... ]
Checks the ARGs for legal options. If the ARGs are omitted, use
the positional parameters. A valid option argument begins with a
`+' or a `-'. An argument not beginning with a `+' or a `-', or
the argument `--', ends the options. Note that a single `-' is
not considered a valid option argument. OPTSTRING contains the
letters that getopts recognizes. If a letter is followed by a
`:', that option is expected to have an argument. The options can
be separated from the argument by blanks.
Each time it is invoked, getopts places the option letter it finds
in the shell parameter NAME, prepended with a `+' when ARG begins
with a `+'. The index of the next ARG is stored in OPTIND. The
option argument, if any, is stored in OPTARG.
The first option to be examined may be changed by explicitly
assigning to OPTIND. OPTIND has an initial value of 1, and is
normally reset to 1 upon exit from a shell function. OPTARG is
not reset and retains its value from the most recent call to
getopts. If either of OPTIND or OPTARG is explicitly unset, it
remains unset, and the index or option argument is not stored.
The option itself is still stored in NAME in this case.
A leading `:' in OPTSTRING causes getopts to store the letter of
any invalid option in OPTARG, and to set NAME to `?' for an
unknown option and to `:' when a required option is missing.
Otherwise, getopts sets NAME to `?' and prints an error message
when an option is invalid. The exit status is nonzero when there
are no more options.
hash [ -Ldfmrv ] [ NAME[=VALUE] ] ...
hash can be used to directly modify the contents of the command
hash table, and the named directory hash table. Normally one would
modify these tables by modifying one's PATH (for the command hash
table) or by creating appropriate shell parameters (for the named
directory hash table). The choice of hash table to work on is
determined by the -d option; without the option the command hash
table is used, and with the option the named directory hash table
is used.
Given no arguments, and neither the -r or -f options, the selected
hash table will be listed in full.
The -r option causes the selected hash table to be emptied. It
will be subsequently rebuilt in the normal fashion. The -f option
causes the selected hash table to be fully rebuilt immediately.
For the command hash table this hashes all the absolute
directories in the PATH, and for the named directory hash table
this adds all users' home directories. These two options cannot
be used with any arguments.
The -m option causes the arguments to be taken as patterns (which
should be quoted) and the elements of the hash table matching
those patterns are printed. This is the only way to display a
limited selection of hash table elements.
For each NAME with a corresponding VALUE, put `NAME' in the
selected hash table, associating it with the pathname `VALUE'. In
the command hash table, this means that whenever `NAME' is used as
a command argument, the shell will try to execute the file given
by `VALUE'. In the named directory hash table, this means that
`VALUE' may be referred to as `~NAME'.
For each NAME with no corresponding VALUE, attempt to add NAME to
the hash table, checking what the appropriate value is in the
normal manner for that hash table. If an appropriate value can't
be found, then the hash table will be unchanged.
The -v option causes hash table entries to be listed as they are
added by explicit specification. If has no effect if used with -f.
If the -L flag is present, then each hash table entry is printed in
the form of a call to hash.
history
Same as fc -l.
integer [ {+|-}Hghilprtux ] [ -LRZ [ N ]] [ NAME[=VALUE] ... ]
Equivalent to typeset -i, except that options irrelevant to
integers are not permitted.
jobs [ -dlprs ] [ JOB ... ]
jobs -Z STRING
Lists information about each given job, or all jobs if JOB is
omitted. The -l flag lists process IDs, and the -p flag lists
process groups. If the -r flag is specified only running jobs
will be listed and if the -s flag is given only stopped jobs are
shown. If the -d flag is given, the directory from which the job
was started (which may not be the current directory of the job)
will also be shown.
The -Z option replaces the shell's argument and environment space
with the given string, truncated if necessary to fit. This will
normally be visible in ps (man page ps(1)) listings. This feature
is typically used by daemons, to indicate their state.
kill [ -s SIGNAL_NAME | -n SIGNAL_NUMBER | -SIG ] JOB ...
kill -l [ SIG ... ]
Sends either SIGTERM or the specified signal to the given jobs or
processes. Signals are given by number or by names, with or
without the `SIG' prefix. If the signal being sent is not `KILL'
or `CONT', then the job will be sent a `CONT' signal if it is
stopped. The argument JOB can be the process ID of a job not in
the job list. In the second form, kill -l, if SIG is not
specified the signal names are listed. Otherwise, for each SIG
that is a name, the corresponding signal number is listed. For
each SIG that is a signal number or a number representing the exit
status of a process which was terminated or stopped by a signal
the name of the signal is printed.
On some systems, alternative signal names are allowed for a few
signals. Typical examples are SIGCHLD and SIGCLD or SIGPOLL and
SIGIO, assuming they correspond to the same signal number. kill
-l will only list the preferred form, however kill -l ALT will
show if the alternative form corresponds to a signal number. For
example, under Linux kill -l IO and kill -l POLL both output 29,
hence kill -IO and kill -POLL have the same effect.
Many systems will allow process IDs to be negative to kill a
process group or zero to kill the current process group.
let ARG ...
Evaluate each ARG as an arithmetic expression. See *Note
Arithmetic Evaluation:: for a description of arithmetic
expressions. The exit status is 0 if the value of the last
expression is nonzero, 1 if it is zero, and 2 if an error occurred.
limit [ -hs ] [ RESOURCE [ LIMIT ] ] ...
Set or display resource limits. Unless the -s flag is given, the
limit applies only the children of the shell. If -s is given
without other arguments, the resource limits of the current shell
is set to the previously set resource limits of the children.
If LIMIT is not specified, print the current limit placed on
RESOURCE, otherwise set the limit to the specified value. If the
-h flag is given, use hard limits instead of soft limits. If no
RESOURCE is given, print all limits.
When looping over multiple resources, the shell will abort
immediately if it detects a badly formed argument. However, if it
fails to set a limit for some other reason it will continue trying
to set the remaining limits.
RESOURCE can be one of:
addressspace
Maximum amount of address space used.
aiomemorylocked
Maximum amount of memory locked in RAM for AIO operations.
aiooperations
Maximum number of AIO operations.
cachedthreads
Maximum number of cached threads.
coredumpsize
Maximum size of a core dump.
cputime
Maximum CPU seconds per process.
datasize
Maximum data size (including stack) for each process.
descriptors
Maximum value for a file descriptor.
filesize
Largest single file allowed.
maxproc
Maximum number of processes.
maxpthreads
Maximum number of threads per process.
memorylocked
Maximum amount of memory locked in RAM.
memoryuse
Maximum resident set size.
msgqueue
Maximum number of bytes in POSIX message queues.
resident
Maximum resident set size.
sigpending
Maximum number of pending signals.
sockbufsize
Maximum size of all socket buffers.
stacksize
Maximum stack size for each process.
vmemorysize
Maximum amount of virtual memory.
Which of these resource limits are available depends on the system.
RESOURCE can be abbreviated to any unambiguous prefix. It can
also be an integer, which corresponds to the integer defined for
the resource by the operating system.
If argument corresponds to a number which is out of the range of
the resources configured into the shell, the shell will try to
read or write the limit anyway, and will report an error if this
fails. As the shell does not store such resources internally, an
attempt to set the limit will fail unless the -s option is present.
LIMIT is a number, with an optional scaling factor, as follows:
Nh
hours
Nk
kilobytes (default)
Nm
megabytes or minutes
[MM:]SS
minutes and seconds
local [ {+|-}AEFHUahlprtux ] [ -LRZi [ N ]] [ NAME[=VALUE] ] ...
Same as typeset, except that the options -g, and -f are not
permitted. In this case the -x option does not force the use of
-g, i.e. exported variables will be local to functions.
log
List all users currently logged in who are affected by the current
setting of the watch parameter.
logout [ N ]
Same as exit, except that it only works in a login shell.
noglob SIMPLE COMMAND
See *Note Precommand Modifiers::.
popd [ [-q] {+|-}N ]
Remove an entry from the directory stack, and perform a cd to the
new top directory. With no argument, the current top entry is
removed. An argument of the form `+N' identifies a stack entry by
counting from the left of the list shown by the dirs command,
starting with zero. An argument of the form -n counts from the
right. If the PUSHD_MINUS option is set, the meanings of `+' and
`-' in this context are swapped.
If the -q (quiet) option is specified, the hook function chpwd and
the functions in the array $chpwd_functions are not called, and
the new directory stack is not printed. This is useful for calls
to popd that do not change the environment seen by an interactive
user.
print [ -abcDilmnNoOpPrsz ] [ -u N ] [ -f FORMAT ] [ -C COLS ]
[ -R [ -en ]] [ ARG ... ]
With the `-f' option the arguments are printed as described by
printf. With no flags or with the flag `-', the arguments are
printed on the standard output as described by echo, with the
following differences: the escape sequence `\M-X' metafies the
character X (sets the highest bit), `\C-X' produces a control
character (`\C-@' and `\C-?' give the characters NUL and delete),
and `\E' is a synonym for `\e'. Finally, if not in an escape
sequence, `\' escapes the following character and is not printed.
-a
Print arguments with the column incrementing first. Only
useful with the -c and -C options.
-b
Recognize all the escape sequences defined for the bindkey
command, see *Note Zle Builtins::.
-c
Print the arguments in columns. Unless -a is also given,
arguments are printed with the row incrementing first.
-C COLS
Print the arguments in COLS columns. Unless -a is also given,
arguments are printed with the row incrementing first.
-D
Treat the arguments as directory names, replacing prefixes
with ~ expressions, as appropriate.
-i
If given together with -o or -O, sorting is performed
case-independently.
-l
Print the arguments separated by newlines instead of spaces.
-m
Take the first argument as a pattern (should be quoted), and
remove it from the argument list together with subsequent
arguments that do not match this pattern.
-n
Do not add a newline to the output.
-N
Print the arguments separated and terminated by nulls.
-o
Print the arguments sorted in ascending order.
-O
Print the arguments sorted in descending order.
-p
Print the arguments to the input of the coprocess.
-P
Perform prompt expansion (see *Note Prompt Expansion::).
-r
Ignore the escape conventions of echo.
-R
Emulate the BSD echo command, which does not process escape
sequences unless the -e flag is given. The -n flag
suppresses the trailing newline. Only the -e and -n flags
are recognized after -R; all other arguments and options are
printed.
-s
Place the results in the history list instead of on the
standard output.
-u N
Print the arguments to file descriptor N.
-z
Push the arguments onto the editing buffer stack, separated
by spaces.
If any of `-m', `-o' or `-O' are used in combination with `-f' and
there are no arguments (after the removal process in the case of
`-m') then nothing is printed.
printf FORMAT [ ARG ... ]
Print the arguments according to the format specification.
Formatting rules are the same as used in C. The same escape
sequences as for echo are recognised in the format. All C
conversion specifications ending in one of csdiouxXeEfgGn are
handled. In addition to this, `%b' can be used instead of `%s' to
cause escape sequences in the argument to be recognised and `%q'
can be used to quote the argument in such a way that allows it to
be reused as shell input. With the numeric format specifiers, if
the corresponding argument starts with a quote character, the
numeric value of the following character is used as the number to
print otherwise the argument is evaluated as an arithmetic
expression. See *Note Arithmetic Evaluation:: for a description of
arithmetic expressions. With `%n', the corresponding argument is
taken as an identifier which is created as an integer parameter.
Normally, conversion specifications are applied to each argument
in order but they can explicitly specify the Nth argument is to be
used by replacing `%' by `%N$' and `*' by `*N$'. It is
recommended that you do not mix references of this explicit style
with the normal style and the handling of such mixed styles may be
subject to future change.
If arguments remain unused after formatting, the format string is
reused until all arguments have been consumed. With the print
builtin, this can be suppressed by using the -r option. If more
arguments are required by the format than have been specified, the
behaviour is as if zero or an empty string had been specified as
the argument.
pushd [ -qsLP ] [ ARG ]
pushd [ -qsLP ] OLD NEW
pushd [ -qsLP ] {+|-}N
Change the current directory, and push the old current directory
onto the directory stack. In the first form, change the current
directory to ARG. If ARG is not specified, change to the second
directory on the stack (that is, exchange the top two entries), or
change to $HOME if the PUSHD_TO_HOME option is set or if there is
only one entry on the stack. Otherwise, ARG is interpreted as it
would be by cd. The meaning of OLD and NEW in the second form is
also the same as for cd.
The third form of pushd changes directory by rotating the
directory list. An argument of the form `+N' identifies a stack
entry by counting from the left of the list shown by the dirs
command, starting with zero. An argument of the form `-N' counts
from the right. If the PUSHD_MINUS option is set, the meanings of
`+' and `-' in this context are swapped.
If the -q (quiet) option is specified, the hook function chpwd and
the functions in the array $chpwd_functions are not called, and
the new directory stack is not printed. This is useful for calls
to pushd that do not change the environment seen by an interactive
user.
If the option -q is not specified and the shell option PUSHD_SILENT
is not set, the directory stack will be printed after a pushd is
performed.
The options -s, -L and -P have the same meanings as for the cd
builtin.
pushln [ ARG ... ]
Equivalent to print -nz.
pwd [ -rLP ]
Print the absolute pathname of the current working directory. If
the -r or the -P flag is specified, or the CHASE_LINKS option is
set and the -L flag is not given, the printed path will not
contain symbolic links.
r
Same as fc -e -.
read [ -rszpqAclneE ] [ -t [ NUM ] ] [ -k [ NUM ] ] [ -d DELIM ] [ -u N ] [ NAME[?PROMPT] ] [ NAME ... ]
Read one line and break it into fields using the characters in
$IFS as separators, except as noted below. The first field is
assigned to the first NAME, the second field to the second NAME,
etc., with leftover fields assigned to the last NAME. If NAME is
omitted then REPLY is used for scalars and reply for arrays.
-r
Raw mode: a `\' at the end of a line does not signify line
continuation and backslashes in the line don't quote the
following character and are not removed.
-s
Don't echo back characters if reading from the terminal.
Currently does not work with the -q option.
-q
Read only one character from the terminal and set NAME to `y'
if this character was `y' or `Y' and to `n' otherwise. With
this flag set the return status is zero only if the character
was `y' or `Y'. Note that this always reads from the
terminal, even if used with the -p or -u or -z flags or with
redirected input. This option may also be used within zle
widgets.
-k [ NUM ]
Read only one (or NUM) characters. All are assigned to the
first NAME, without word splitting. This flag is ignored
when -q is present. Input is read from the terminal unless
one of -u or -p is present. This option may also be used
within zle widgets.
Note that despite the mnemonic `key' this option does read
full characters, which may consist of multiple bytes if the
option MULTIBYTE is set.
-z
Read one entry from the editor buffer stack and assign it to
the first NAME, without word splitting. Text is pushed onto
the stack with `print -z' or with push-line from the line
editor (see *Note Zsh Line Editor::). This flag is ignored
when the -k or -q flags are present.
-e
-E
The input read is printed (echoed) to the standard output.
If the -e flag is used, no input is assigned to the
parameters.
-A
The first NAME is taken as the name of an array and all words
are assigned to it.
-c
-l
These flags are allowed only if called inside a function used
for completion (specified with the -K flag to compctl). If
the -c flag is given, the words of the current command are
read. If the -l flag is given, the whole line is assigned as
a scalar. If both flags are present, -l is used and -c is
ignored.
-n
Together with -c, the number of the word the cursor is on is
read. With -l, the index of the character the cursor is on is
read. Note that the command name is word number 1, not word
0, and that when the cursor is at the end of the line, its
character index is the length of the line plus one.
-u N
Input is read from file descriptor N.
-p
Input is read from the coprocess.
-d DELIM
Input is terminated by the first character of DELIM instead of
by newline.
-t [ NUM ]
Test if input is available before attempting to read. If NUM
is present, it must begin with a digit and will be evaluated
to give a number of seconds, which may be a floating point
number; in this case the read times out if input is not
available within this time. If NUM is not present, it is
taken to be zero, so that read returns immediately if no
input is available. If no input is available, return status
1 and do not set any variables.
This option is not available when reading from the editor
buffer with -z, when called from within completion with -c or
-l, with -q which clears the input queue before reading, or
within zle where other mechanisms should be used to test for
input.
Note that read does not attempt to alter the input processing
mode. The default mode is canonical input, in which an
entire line is read at a time, so usually `read -t' will not
read anything until an entire line has been typed. However,
when reading from the terminal with -k input is processed one
key at a time; in this case, only availability of the first
character is tested, so that e.g. `read -t -k 2' can still
block on the second character. Use two instances of `read -t
-k' if this is not what is wanted.
If the first argument contains a `?', the remainder of this word
is used as a PROMPT on standard error when the shell is
interactive.
The value (exit status) of read is 1 when an end-of-file is
encountered, or when -c or -l is present and the command is not
called from a compctl function, or as described for -q. Otherwise
the value is 0.
The behavior of some combinations of the -k, -p, -q, -u and -z
flags is undefined. Presently -q cancels all the others, -p
cancels -u, -k cancels -z, and otherwise -z cancels both -p and -u.
The -c or -l flags cancel any and all of -kpquz.
readonly
Same as typeset -r.
rehash
Same as hash -r.
return [ N ]
Causes a shell function or `.' script to return to the invoking
script with the return status specified by N. If N is omitted,
the return status is that of the last command executed.
If return was executed from a trap in a TRAPNAL function, the
effect is different for zero and non-zero return status. With zero
status (or after an implicit return at the end of the trap), the
shell will return to whatever it was previously processing; with a
non-zero status, the shell will behave as interrupted except that
the return status of the trap is retained. Note that the numeric
value of the signal which caused the trap is passed as the first
argument, so the statement `return $((128+$1))' will return the
same status as if the signal had not been trapped.
sched
See *Note The zsh/sched Module::.
set [ {+|-}OPTIONS | {+|-}o [ OPTION_NAME ] ] ... [ {+|-}A [ NAME ] ] [ ARG ... ]
Set the options for the shell and/or set the positional
parameters, or declare and set an array. If the -s option is
given, it causes the specified arguments to be sorted before
assigning them to the positional parameters (or to the array NAME
if -A is used). With +s sort arguments in descending order. For
the meaning of the other flags, see *Note Options::. Flags may be
specified by name using the -o option. If no option name is
supplied with -o, the current option states are printed: see the
description of setopt below for more information on the format.
With +o they are printed in a form that can be used as input to
the shell.
If the -A flag is specified, NAME is set to an array containing
the given ARGs; if no NAME is specified, all arrays are printed
together with their values.
If +A is used and NAME is an array, the given arguments will
replace the initial elements of that array; if no NAME is
specified, all arrays are printed without their values.
The behaviour of arguments after -A NAME or +A NAME depends on
whether the option KSH_ARRAYS is set. If it is not set, all
arguments following NAME are treated as values for the array,
regardless of their form. If the option is set, normal option
processing continues at that point; only regular arguments are
treated as values for the array. This means that
set -A array -x -- foo
sets array to `-x -- foo' if KSH_ARRAYS is not set, but sets the
array to foo and turns on the option `-x' if it is set.
If the -A flag is not present, but there are arguments beyond the
options, the positional parameters are set. If the option list
(if any) is terminated by `--', and there are no further
arguments, the positional parameters will be unset.
If no arguments and no `--' are given, then the names and values of
all parameters are printed on the standard output. If the only
argument is `+', the names of all parameters are printed.
For historical reasons, `set -' is treated as `set +xv' and `set -
ARGS' as `set +xv - ARGS' when in any other emulation mode than
zsh's native mode.
setcap
See *Note The zsh/cap Module::.
setopt [ {+|-}OPTIONS | {+|-}o OPTION_NAME ] [ NAME ... ]
Set the options for the shell. All options specified either with
flags or by name are set.
If no arguments are supplied, the names of all options currently
set are printed. The form is chosen so as to minimize the
differences from the default options for the current emulation
(the default emulation being native zsh, shown as <Z> in *Note
Description of Options::). Options that are on by default for the
emulation are shown with the prefix no only if they are off, while
other options are shown without the prefix no and only if they are
on. In addition to options changed from the default state by the
user, any options activated automatically by the shell (for
example, SHIN_STDIN or INTERACTIVE) will be shown in the list.
The format is further modified by the option KSH_OPTION_PRINT,
however the rationale for choosing options with or without the no
prefix remains the same in this case.
If the -m flag is given the arguments are taken as patterns (which
should be quoted to protect them from filename expansion), and all
options with names matching these patterns are set.
shift [ N ] [ NAME ... ]
The positional parameters ${N+1} ... are renamed to $1 ..., where
N is an arithmetic expression that defaults to 1. If any NAMEs
are given then the arrays with these names are shifted instead of
the positional parameters.
source FILE [ ARG ... ]
Same as `.', except that the current directory is always searched
and is always searched first, before directories in $path.
stat
See *Note The zsh/stat Module::.
suspend [ -f ]
Suspend the execution of the shell (send it a SIGTSTP) until it
receives a SIGCONT. Unless the -f option is given, this will
refuse to suspend a login shell.
test [ ARG ... ]
[ [ ARG ... ] ]
Like the system version of test. Added for compatibility; use
conditional expressions instead (see *Note Conditional
Expressions::). The main differences between the conditional
expression syntax and the test and [ builtins are: these commands
are not handled syntactically, so for example an empty variable
expansion may cause an argument to be omitted; syntax errors cause
status 2 to be returned instead of a shell error; and arithmetic
operators expect integer arguments rather than arithmetic
expressions.
The command attempts to implement POSIX and its extensions where
these are specified. Unfortunately there are intrinsic
ambiguities in the syntax; in particular there is no distinction
between test operators and strings that resemble them. The
standard attempts to resolve these for small numbers of arguments
(up to four); for five or more arguments compatibility cannot be
relied on. Users are urged wherever possible to use the `[[' test
syntax which does not have these ambiguities.
times
Print the accumulated user and system times for the shell and for
processes run from the shell.
trap [ ARG ] [ SIG ... ]
ARG is a series of commands (usually quoted to protect it from
immediate evaluation by the shell) to be read and executed when
the shell receives any of the signals specified by one or more SIG
args. Each SIG can be given as a number, or as the name of a
signal either with or without the string SIG in front (e.g. 1,
HUP, and SIGHUP are all the same signal).
If ARG is `-', then the specified signals are reset to their
defaults, or, if no SIG args are present, all traps are reset.
If ARG is an empty string, then the specified signals are ignored
by the shell (and by the commands it invokes).
If ARG is omitted but one or more SIG args are provided (i.e. the
first argument is a valid signal number or name), the effect is the
same as if ARG had been specified as `-'.
The trap command with no arguments prints a list of commands
associated with each signal.
If SIG is ZERR then ARG will be executed after each command with a
nonzero exit status. ERR is an alias for ZERR on systems that
have no SIGERR signal (this is the usual case).
If SIG is DEBUG then ARG will be executed before each command if
the option DEBUG_BEFORE_CMD is set (as it is by default), else
after each command. Here, a `command' is what is described as a
`sublist' in the shell grammar, see *Note Simple Commands &
Pipelines::. If DEBUG_BEFORE_CMD is set various additional
features are available. First, it is possible to skip the next
command by setting the option ERR_EXIT; see the description of the
ERR_EXIT option in *Note Description of Options::. Also, the
shell parameter ZSH_DEBUG_CMD is set to the string corresponding
to the command to be executed following the trap. Note that this
string is reconstructed from the internal format and may not be
formatted the same way as the original text. The parameter is
unset after the trap is executed.
If SIG is 0 or EXIT and the trap statement is executed inside the
body of a function, then the command ARG is executed after the
function completes. The value of $? at the start of execution is
the exit status of the shell or the return status of the function
exiting. If SIG is 0 or EXIT and the trap statement is not
executed inside the body of a function, then the command ARG is
executed when the shell terminates.
ZERR, DEBUG, and EXIT traps are not executed inside other traps.
ZERR and DEBUG traps are kept within subshells, while other traps
are reset.
Note that traps defined with the trap builtin are slightly
different from those defined as `TRAPNAL () { ... }', as the
latter have their own function environment (line numbers, local
variables, etc.) while the former use the environment of the
command in which they were called. For example,
trap 'print $LINENO' DEBUG
will print the line number of a command executed after it has run,
while
TRAPDEBUG() { print $LINENO; }
will always print the number zero.
Alternative signal names are allowed as described under kill above.
Defining a trap under either name causes any trap under an
alternative name to be removed. However, it is recommended that
for consistency users stick exclusively to one name or another.
true [ ARG ... ]
Do nothing and return an exit status of 0.
ttyctl -fu
The -f option freezes the tty, and -u unfreezes it. When the tty
is frozen, no changes made to the tty settings by external
programs will be honored by the shell, except for changes in the
size of the screen; the shell will simply reset the settings to
their previous values as soon as each command exits or is
suspended. Thus, stty and similar programs have no effect when
the tty is frozen. Without options it reports whether the
terminal is frozen or not.
type [ -wfpams ] NAME ...
Equivalent to whence -v.
typeset [ {+|-}AEFHUafghklprtuxmz ] [ -LRZi [ N ]] [ NAME[=VALUE] ... ]
typeset -T [ {+|-}Urux ] [ -LRZ [ N ]] SCALAR[=VALUE] ARRAY [ SEP ]
Set or display attributes and values for shell parameters.
A parameter is created for each NAME that does not already refer
to one. When inside a function, a new parameter is created for
every NAME (even those that already exist), and is unset again
when the function completes. See *Note Local Parameters::. The
same rules apply to special shell parameters, which retain their
special attributes when made local.
For each NAME=VALUE assignment, the parameter NAME is set to
VALUE. Note that arrays currently cannot be assigned in typeset
expressions, only scalars and integers. Unless the option
KSH_TYPESET is set, normal expansion rules apply to assignment
arguments, so VALUE may be split into separate words; if the
option is set, assignments which can be recognised when expansion
is performed are treated as single words. For example the command
typeset vbl=$(echo one two) is treated as having one argument if
KSH_TYPESET is set, but otherwise is treated as having the two
arguments vbl=one and two.
If the shell option TYPESET_SILENT is not set, for each remaining
NAME that refers to a parameter that is set, the name and value of
the parameter are printed in the form of an assignment. Nothing
is printed for newly-created parameters, or when any attribute
flags listed below are given along with the NAME. Using `+'
instead of minus to introduce an attribute turns it off.
If the -p option is given, parameters and values are printed in the
form of a typeset command and an assignment (which will be printed
separately for arrays and associative arrays), regardless of other
flags and options. Note that the -h flag on parameters is
respected; no value will be shown for these parameters.
If the -T option is given, two or three arguments must be present
(an exception is that zero arguments are allowed to show the list
of parameters created in this fashion). The first two are the
name of a scalar and an array parameter (in that order) that will
be tied together in the manner of $PATH and $path. The optional
third argument is a single-character separator which will be used
to join the elements of the array to form the scalar; if absent, a
colon is used, as with $PATH. Only the first character of the
separator is significant; any remaining characters are ignored.
Only the scalar parameter may be assigned an initial value. Both
the scalar and the array may otherwise be manipulated as normal.
If one is unset, the other will automatically be unset too. There
is no way of untying the variables without unsetting them, or
converting the type of one of them with another typeset command;
+T does not work, assigning an array to SCALAR is an error, and
assigning a scalar to ARRAY sets it to be a single-element array.
Note that both `typeset -xT ...' and `export -T ...' work, but
only the scalar will be marked for export. Setting the value
using the scalar version causes a split on all separators (which
cannot be quoted).
The -g (global) flag is treated specially: it means that any
resulting parameter will not be restricted to local scope. Note
that this does not necessarily mean that the parameter will be
global, as the flag will apply to any existing parameter (even if
unset) from an enclosing function. This flag does not affect the
parameter after creation, hence it has no effect when listing
existing parameters, nor does the flag +g have any effect except
in combination with -m (see below).
If no NAME is present, the names and values of all parameters are
printed. In this case the attribute flags restrict the display to
only those parameters that have the specified attributes, and
using `+' rather than `-' to introduce the flag suppresses
printing of the values of parameters when there is no parameter
name. Also, if the last option is the word `+', then names are
printed but values are not.
If the -m flag is given the NAME arguments are taken as patterns
(which should be quoted). With no attribute flags, all parameters
(or functions with the -f flag) with matching names are printed
(the shell option TYPESET_SILENT is not used in this case). Note
that -m is ignored if no patterns are given. If the +g flag is
combined with -m, a new local parameter is created for every
matching parameter that is not already local. Otherwise -m
applies all other flags or assignments to the existing parameters.
Except when assignments are made with NAME=VALUE, using +m forces
the matching parameters to be printed, even inside a function.
If no attribute flags are given and either no -m flag is present or
the +m form was used, each parameter name printed is preceded by a
list of the attributes of that parameter (array, association,
exported, integer, readonly). If +m is used with attribute flags,
and all those flags are introduced with +, the matching parameter
names are printed but their values are not.
Attribute flags that transform the final value (-L, -R, -Z, -l, u)
are only applied to the expanded value at the point of a parameter
expansion expression using `$'. They are not applied when a
parameter is retrieved internally by the shell for any purpose.
The following attribute flags may be specified:
-A
The names refer to associative array parameters; see *Note
Array Parameters::.
-L
Left justify and remove leading blanks from VALUE. If N is
nonzero, it defines the width of the field. If N is zero,
the width is determined by the width of the value of the
first assignment. In the case of numeric parameters, the
length of the complete value assigned to the parameter is
used to determine the width, not the value that would be
output.
The width is the count of characters, which may be multibyte
characters if the MULTIBYTE option is in effect. Note that
the screen width of the character is not taken into account;
if this is required, use padding with parameter expansion
flags ${(ml...)...} as described in `Parameter Expansion
Flags' in *Note Parameter Expansion::.
When the parameter is expanded, it is filled on the right with
blanks or truncated if necessary to fit the field. Note
truncation can lead to unexpected results with numeric
parameters. Leading zeros are removed if the -Z flag is also
set.
-R
Similar to -L, except that right justification is used; when
the parameter is expanded, the field is left filled with
blanks or truncated from the end. May not be combined with
the -Z flag.
-U
For arrays (but not for associative arrays), keep only the
first occurrence of each duplicated value. This may also be
set for colon-separated special parameters like PATH or
FIGNORE, etc. This flag has a different meaning when used
with -f; see below.
-Z
Specially handled if set along with the -L flag. Otherwise,
similar to -R, except that leading zeros are used for padding
instead of blanks if the first non-blank character is a digit.
Numeric parameters are specially handled: they are always
eligible for padding with zeroes, and the zeroes are inserted
at an appropriate place in the output.
-a
The names refer to array parameters. An array parameter may
be created this way, but it may not be assigned to in the
typeset statement. When displaying, both normal and
associative arrays are shown.
-f
The names refer to functions rather than parameters. No
assignments can be made, and the only other valid flags are
-t, -k, -u, -U and -z. The flag -t turns on execution
tracing for this function. The -u and -U flags cause the
function to be marked for autoloading; -U also causes alias
expansion to be suppressed when the function is loaded. The
fpath parameter will be searched to find the function
definition when the function is first referenced; see *Note
Functions::. The -k and -z flags make the function be loaded
using ksh-style or zsh-style autoloading respectively. If
neither is given, the setting of the KSH_AUTOLOAD option
determines how the function is loaded.
-h
Hide: only useful for special parameters (those marked `<S>'
in the table in *Note Parameters Set By The Shell::), and for
local parameters with the same name as a special parameter,
though harmless for others. A special parameter with this
attribute will not retain its special effect when made local.
Thus after `typeset -h PATH', a function containing `typeset
PATH' will create an ordinary local parameter without the
usual behaviour of PATH. Alternatively, the local parameter
may itself be given this attribute; hence inside a function
`typeset -h PATH' creates an ordinary local parameter and the
special PATH parameter is not altered in any way. It is also
possible to create a local parameter using `typeset +h
SPECIAL', where the local copy of SPECIAL will retain its
special properties regardless of having the -h attribute.
Global special parameters loaded from shell modules
(currently those in zsh/mapfile and zsh/parameter) are
automatically given the -h attribute to avoid name clashes.
-H
Hide value: specifies that typeset will not display the value
of the parameter when listing parameters; the display for
such parameters is always as if the `+' flag had been given.
Use of the parameter is in other respects normal, and the
option does not apply if the parameter is specified by name,
or by pattern with the -m option. This is on by default for
the parameters in the zsh/parameter and zsh/mapfile modules.
Note, however, that unlike the -h flag this is also useful
for non-special parameters.
-i
Use an internal integer representation. If N is nonzero it
defines the output arithmetic base, otherwise it is
determined by the first assignment. Bases from 2 to 36
inclusive are allowed.
-E
Use an internal double-precision floating point
representation. On output the variable will be converted to
scientific notation. If N is nonzero it defines the number
of significant figures to display; the default is ten.
-F
Use an internal double-precision floating point
representation. On output the variable will be converted to
fixed-point decimal notation. If N is nonzero it defines the
number of digits to display after the decimal point; the
default is ten.
-l
Convert the result to lower case whenever the parameter is
expanded. The value is _not_ converted when assigned.
-r
The given NAMEs are marked readonly. Note that if NAME is a
special parameter, the readonly attribute can be turned on,
but cannot then be turned off.
-t
Tags the named parameters. Tags have no special meaning to
the shell. This flag has a different meaning when used with
-f; see above.
-u
Convert the result to upper case whenever the parameter is
expanded. The value is _not_ converted when assigned. This
flag has a different meaning when used with -f; see above.
-x
Mark for automatic export to the environment of subsequently
executed commands. If the option GLOBAL_EXPORT is set, this
implies the option -g, unless +g is also explicitly given; in
other words the parameter is not made local to the enclosing
function. This is for compatibility with previous versions
of zsh.
ulimit [ [ -SHacdfilmnpqstvx | -N RESOURCE [ LIMIT ] ... ]
Set or display resource limits of the shell and the processes
started by the shell. The value of LIMIT can be a number in the
unit specified below or the value `unlimited'. By default, only
soft limits are manipulated. If the -H flag is given use hard
limits instead of soft limits. If the -S flag is given together
with the -H flag set both hard and soft limits. If no options are
used, the file size limit (-f) is assumed. If LIMIT is omitted
the current value of the specified resources are printed. When
more than one resource values are printed the limit name and unit
is printed before each value.
When looping over multiple resources, the shell will abort
immediately if it detects a badly formed argument. However, if it
fails to set a limit for some other reason it will continue trying
to set the remaining limits.
-a
Lists all of the current resource limits.
-c
512-byte blocks on the size of core dumps.
-d
K-bytes on the size of the data segment.
-f
512-byte blocks on the size of files written.
-i
The number of pending signals.
-l
K-bytes on the size of locked-in memory.
-m
K-bytes on the size of physical memory.
-n
open file descriptors.
-q
Bytes in POSIX message queues.
-s
K-bytes on the size of the stack.
-t
CPU seconds to be used.
-u
processes available to the user.
-v
K-bytes on the size of virtual memory. On some systems this
refers to the limit called `address space'.
-x
The number of locks on files.
A resource may also be specified by integer in the form `-N
RESOURCE', where RESOURCE corresponds to the integer defined for
the resource by the operating system. This may be used to set the
limits for resources known to the shell which do not correspond to
option letters. Such limits will be shown by number in the output
of `ulimit -a'.
The number may alternatively be out of the range of limits
compiled into the shell. The shell will try to read or write the
limit anyway, and will report an error if this fails.
umask [ -S ] [ MASK ]
The umask is set to MASK. MASK can be either an octal number or a
symbolic value as described in man page chmod(1). If MASK is
omitted, the current value is printed. The -S option causes the
mask to be printed as a symbolic value. Otherwise, the mask is
printed as an octal number. Note that in the symbolic form the
permissions you specify are those which are to be allowed (not
denied) to the users specified.
unalias
Same as unhash -a.
unfunction
Same as unhash -f.
unhash [ -adfms ] NAME ...
Remove the element named NAME from an internal hash table. The
default is remove elements from the command hash table. The -a
option causes unhash to remove regular or global aliases; note
when removing a global aliases that the argument must be quoted to
prevent it from being expanded before being passed to the command.
The -s option causes unhash to remove suffix aliases. The -f
option causes unhash to remove shell functions. The -d options
causes unhash to remove named directories. If the -m flag is given
the arguments are taken as patterns (should be quoted) and all
elements of the corresponding hash table with matching names will
be removed.
unlimit [ -hs ] RESOURCE ...
The resource limit for each RESOURCE is set to the hard limit. If
the -h flag is given and the shell has appropriate privileges, the
hard resource limit for each RESOURCE is removed. The resources
of the shell process are only changed if the -s flag is given.
unset [ -fmv ] NAME ...
Each named parameter is unset. Local parameters remain local even
if unset; they appear unset within scope, but the previous value
will still reappear when the scope ends.
Individual elements of associative array parameters may be unset
by using subscript syntax on NAME, which should be quoted (or the
entire command prefixed with noglob) to protect the subscript from
filename generation.
If the -m flag is specified the arguments are taken as patterns
(should be quoted) and all parameters with matching names are
unset. Note that this cannot be used when unsetting associative
array elements, as the subscript will be treated as part of the
pattern.
The -v flag specifies that NAME refers to parameters. This is the
default behaviour.
unset -f is equivalent to unfunction.
unsetopt [ {+|-}OPTIONS | {+|-}o OPTION_NAME ] [ NAME ... ]
Unset the options for the shell. All options specified either
with flags or by name are unset. If no arguments are supplied,
the names of all options currently unset are printed. If the -m
flag is given the arguments are taken as patterns (which should be
quoted to preserve them from being interpreted as glob patterns),
and all options with names matching these patterns are unset.
vared
See *Note Zle Builtins::.
wait [ JOB ... ]
Wait for the specified jobs or processes. If JOB is not given
then all currently active child processes are waited for. Each
JOB can be either a job specification or the process ID of a job
in the job table. The exit status from this command is that of
the job waited for.
whence [ -vcwfpams ] NAME ...
For each name, indicate how it would be interpreted if used as a
command name.
-v
Produce a more verbose report.
-c
Print the results in a `csh'-like format. This takes
precedence over -v.
-w
For each NAME, print `NAME: WORD' where WORD is one of alias,
builtin, command, function, hashed, reserved or none,
according as NAME corresponds to an alias, a built-in
command, an external command, a shell function, a command
defined with the hash builtin, a reserved word, or is not
recognised. This takes precedence over -v and -c.
-f
Causes the contents of a shell function to be displayed,
which would otherwise not happen unless the -c flag were used.
-p
Do a path search for NAME even if it is an alias, reserved
word, shell function or builtin.
-a
Do a search for all occurrences of NAME throughout the
command path. Normally only the first occurrence is printed.
-m
The arguments are taken as patterns (should be quoted), and
the information is displayed for each command matching one of
these patterns.
-s
If a pathname contains symlinks, print the symlink-free
pathname as well.
where [ -wpms ] NAME ...
Equivalent to whence -ca.
which [ -wpams ] NAME ...
Equivalent to whence -c.
zcompile [ -U ] [ -z | -k ] [ -R | -M ] FILE [ NAME ... ]
zcompile -ca [ -m ] [ -R | -M ] FILE [ NAME ... ]
zcompile -t FILE [ NAME ... ]
This builtin command can be used to compile functions or scripts,
storing the compiled form in a file, and to examine files
containing the compiled form. This allows faster autoloading of
functions and execution of scripts by avoiding parsing of the text
when the files are read.
The first form (without the -c, -a or -t options) creates a
compiled file. If only the FILE argument is given, the output
file has the name `FILE.zwc' and will be placed in the same
directory as the FILE. The shell will load the compiled file
instead of the normal function file when the function is
autoloaded; see *Note Functions:: for a description of how
autoloaded functions are searched. The extension .zwc stands for
`zsh word code'.
If there is at least one NAME argument, all the named files are
compiled into the output FILE given as the first argument. If
FILE does not end in .zwc, this extension is automatically
appended. Files containing multiple compiled functions are called
`digest' files, and are intended to be used as elements of the
FPATH/fpath special array.
The second form, with the -c or -a options, writes the compiled
definitions for all the named functions into FILE. For -c, the
names must be functions currently defined in the shell, not those
marked for autoloading. Undefined functions that are marked for
autoloading may be written by using the -a option, in which case
the fpath is searched and the contents of the definition files for
those functions, if found, are compiled into FILE. If both -c and
-a are given, names of both defined functions and functions marked
for autoloading may be given. In either case, the functions in
files written with the -c or -a option will be autoloaded as if the
KSH_AUTOLOAD option were unset.
The reason for handling loaded and not-yet-loaded functions with
different options is that some definition files for autoloading
define multiple functions, including the function with the same
name as the file, and, at the end, call that function. In such
cases the output of `zcompile -c' does not include the additional
functions defined in the file, and any other initialization code
in the file is lost. Using `zcompile -a' captures all this extra
information.
If the -m option is combined with -c or -a, the NAMEs are used as
patterns and all functions whose names match one of these patterns
will be written. If no NAME is given, the definitions of all
functions currently defined or marked as autoloaded will be
written.
The third form, with the -t option, examines an existing compiled
file. Without further arguments, the names of the original files
compiled into it are listed. The first line of output shows the
version of the shell which compiled the file and how the file will
be used (i.e. by reading it directly or by mapping it into memory).
With arguments, nothing is output and the return status is set to
zero if definitions for _all_ NAMEs were found in the compiled
file, and non-zero if the definition for at least one NAME was not
found.
Other options:
-U
Aliases are not expanded when compiling the NAMEd files.
-R
When the compiled file is read, its contents are copied into
the shell's memory, rather than memory-mapped (see -M). This
happens automatically on systems that do not support memory
mapping.
When compiling scripts instead of autoloadable functions, it
is often desirable to use this option; otherwise the whole
file, including the code to define functions which have
already been defined, will remain mapped, consequently
wasting memory.
-M
The compiled file is mapped into the shell's memory when
read. This is done in such a way that multiple instances of
the shell running on the same host will share this mapped
file. If neither -R nor -M is given, the zcompile builtin
decides what to do based on the size of the compiled file.
-k
-z
These options are used when the compiled file contains
functions which are to be autoloaded. If -z is given, the
function will be autoloaded as if the KSH_AUTOLOAD option is
_not_ set, even if it is set at the time the compiled file is
read, while if the -k is given, the function will be loaded
as if KSH_AUTOLOAD _is_ set. These options also take
precedence over any -k or -z options specified to the
autoload builtin. If neither of these options is given, the
function will be loaded as determined by the setting of the
KSH_AUTOLOAD option at the time the compiled file is read.
These options may also appear as many times as necessary
between the listed NAMEs to specify the loading style of all
following functions, up to the next -k or -z.
The created file always contains two versions of the compiled
format, one for big-endian machines and one for small-endian
machines. The upshot of this is that the compiled file is machine
independent and if it is read or mapped, only one half of the file
is actually used (and mapped).
zformat
See *Note The zsh/zutil Module::.
zftp
See *Note The zsh/zftp Module::.
zle
See *Note Zle Builtins::.
zmodload [ -dL ] [ ... ]
zmodload -F [ -lLme -P param ] MODULE [+-]FEATURE...
zmodload -e [ -A ] [ ... ]
zmodload [ -a [ -bcpf [ -I ] ] ] [ -iL ] ...
zmodload -u [ -abcdpf [ -I ] ] [ -iL ] ...
zmodload -A [ -L ] [ MODALIAS[=MODULE] ... ]
zmodload -R MODALIAS ...
Performs operations relating to zsh's loadable modules. Loading
of modules while the shell is running (`dynamical loading') is not
available on all operating systems, or on all installations on a
particular operating system, although the zmodload command itself
is always available and can be used to manipulate modules built
into versions of the shell executable without dynamical loading.
Without arguments the names of all currently loaded binary modules
are printed. The -L option causes this list to be in the form of a
series of zmodload commands. Forms with arguments are:
zmodload [ -i ] NAME ...
zmodload -u [ -i ] NAME ...
In the simplest case, zmodload loads a binary module. The
module must be in a file with a name consisting of the
specified NAME followed by a standard suffix, usually `.so'
(`.sl' on HPUX). If the module to be loaded is already
loaded the duplicate module is ignored. If zmodload detects
an inconsistency, such as an invalid module name or circular
dependency list, the current code block is aborted. Hence
`zmodload MODULE 2>/dev/null' is sufficient to test whether a
module is available. If it is available, the module is
loaded if necessary, while if it is not available, non-zero
status is silently returned. The option -i is accepted for
compatibility but has no effect.
The NAMEd module is searched for in the same way a command
is, using $module_path instead of $path. However, the path
search is performed even when the module name contains a `/',
which it usually does. There is no way to prevent the path
search.
If the module supports features (see below), zmodload tries to
enable all features when loading a module. If the module was
successfully loaded but not all features could be enabled,
zmodload returns status 2.
With -u, zmodload unloads modules. The same NAME must be
given that was given when the module was loaded, but it is not
necessary for the module to exist in the filesystem. The -i
option suppresses the error if the module is already unloaded
(or was never loaded).
Each module has a boot and a cleanup function. The module
will not be loaded if its boot function fails. Similarly a
module can only be unloaded if its cleanup function runs
successfully.
zmodload -F [ -almLe -P param ] MODULE [+-]FEATURE...
zmodload -F allows more selective control over the features
provided by modules. With no options apart from -F, the
module named MODULE is loaded, if it was not already loaded,
and the list of FEATUREs is set to the required state. If no
FEATUREs are specified, the module is loaded, if it was not
already loaded, but the state of features is unchanged. Each
feature may be preceded by a + to turn the feature on, or -
to turn it off; the + is assumed if neither character is
present. Any feature not explicitly mentioned is left in its
current state; if the module was not previously loaded this
means any such features will remain disabled. The return
status is zero if all features were set, 1 if the module
failed to load, and 2 if some features could not be set (for
example, a parameter couldn't be added because there was a
different parameter of the same name) but the module was
loaded.
The standard features are builtins, conditions, parameters
and math functions; these are indicated by the prefix `b:',
`c:' (`C:' for an infix condition), `p:' and `f:',
respectively, followed by the name that the corresponding
feature would have in the shell. For example, `b:strftime'
indicates a builtin named strftime and p:EPOCHSECONDS
indicates a parameter named EPOCHSECONDS. The module may
provide other (`abstract') features of its own as indicated
by its documentation; these have no prefix.
With -l or -L, features provided by the module are listed.
With -l alone, a list of features together with their states
is shown, one feature per line. With -L alone, a zmodload -F
command that would cause enabled features of the module to be
turned on is shown. With -lL, a zmodload -F command that
would cause all the features to be set to their current state
is shown. If one of these combinations is given the option
-P PARAM then the parameter param is set to an array of
features, either features together with their state or (if -L
alone is given) enabled features.
With the option -L the module name may be omitted; then a list
of all enabled features for all modules providing features is
printed in the form of zmodload -F commands. If -l is also
given, the state of both enabled and disabled features is
output in that form.
A set of features may be provided together with -l or -L and a
module name; in that case only the state of those features is
considered. Each feature may be preceded by + or - but the
character has no effect. If no set of features is provided,
all features are considered.
With -e, the command first tests that the module is loaded;
if it is not, status 1 is returned. If the module is loaded,
the list of features given as an argument is examined. Any
feature given with no prefix is simply tested to see if the
module provides it; any feature given with a prefix + or - is
tested to see if is provided and in the given state. If the
tests on all features in the list succeed, status 0 is
returned, else status 1.
With -m, each entry in the given list of features is taken as
a pattern to be matched against the list of features provided
by the module. An initial + or - must be given explicitly.
This may not be combined with the -a option as autoloads must
be specified explicitly.
With -a, the given list of features is marked for autoload
from the specified module, which may not yet be loaded. An
optional + may appear before the feature name. If the
feature is prefixed with -, any existing autoload is removed.
The options -l and -L may be used to list autoloads.
Autoloading is specific to individual features; when the
module is loaded only the requested feature is enabled.
Autoload requests are preserved if the module is subsequently
unloaded until an explicit `zmodload -Fa MODULE -FEATURE' is
issued. It is not an error to request an autoload for a
feature of a module that is already loaded.
When the module is loaded each autoload is checked against
the features actually provided by the module; if the feature
is not provided the autoload request is deleted. A warning
message is output; if the module is being loaded to provide a
different feature, and that autoload is successful, there is
no effect on the status of the current command. If the
module is already loaded at the time when zmodload -Fa is
run, an error message is printed and status 1 returned.
zmodload -Fa can be used with the -l, -L, -e and -P options
for listing and testing the existence of autoloadable
features. In this case -l is ignored if -L is specified.
zmodload -FaL with no module name lists autoloads for all
modules.
Note that only standard features as described above can be
autoloaded; other features require the module to be loaded
before enabling.
zmodload -d [ -L ] [ NAME ]
zmodload -d NAME DEP ...
zmodload -ud NAME [ DEP ... ]
The -d option can be used to specify module dependencies.
The modules named in the second and subsequent arguments will
be loaded before the module named in the first argument.
With -d and one argument, all dependencies for that module
are listed. With -d and no arguments, all module
dependencies are listed. This listing is by default in a
Makefile-like format. The -L option changes this format to a
list of zmodload -d commands.
If -d and -u are both used, dependencies are removed. If
only one argument is given, all dependencies for that module
are removed.
zmodload -ab [ -L ]
zmodload -ab [ -i ] NAME [ BUILTIN ... ]
zmodload -ub [ -i ] BUILTIN ...
The -ab option defines autoloaded builtins. It defines the
specified BUILTINs. When any of those builtins is called,
the module specified in the first argument is loaded and all
its features are enabled (for selective control of features
use `zmodload -F -a' as described above). If only the NAME
is given, one builtin is defined, with the same name as the
module. -i suppresses the error if the builtin is already
defined or autoloaded, but not if another builtin of the same
name is already defined.
With -ab and no arguments, all autoloaded builtins are
listed, with the module name (if different) shown in
parentheses after the builtin name. The -L option changes
this format to a list of zmodload -a commands.
If -b is used together with the -u option, it removes builtins
previously defined with -ab. This is only possible if the
builtin is not yet loaded. -i suppresses the error if the
builtin is already removed (or never existed).
Autoload requests are retained if the module is subsequently
unloaded until an explicit `zmodload -ub BUILTIN' is issued.
zmodload -ac [ -IL ]
zmodload -ac [ -iI ] NAME [ COND ... ]
zmodload -uc [ -iI ] COND ...
The -ac option is used to define autoloaded condition codes.
The COND strings give the names of the conditions defined by
the module. The optional -I option is used to define infix
condition names. Without this option prefix condition names
are defined.
If given no condition names, all defined names are listed (as
a series of zmodload commands if the -L option is given).
The -uc option removes definitions for autoloaded conditions.
zmodload -ap [ -L ]
zmodload -ap [ -i ] NAME [ PARAMETER ... ]
zmodload -up [ -i ] PARAMETER ...
The -p option is like the -b and -c options, but makes
zmodload work on autoloaded parameters instead.
zmodload -af [ -L ]
zmodload -af [ -i ] NAME [ FUNCTION ... ]
zmodload -uf [ -i ] FUNCTION ...
The -f option is like the -b, -p, and -c options, but makes
zmodload work on autoloaded math functions instead.
zmodload -a [ -L ]
zmodload -a [ -i ] NAME [ BUILTIN ... ]
zmodload -ua [ -i ] BUILTIN ...
Equivalent to -ab and -ub.
zmodload -e [ -A ] [ STRING ... ]
The -e option without arguments lists all loaded modules; if
the -A option is also given, module aliases corresponding to
loaded modules are also shown. If arguments are provided,
nothing is printed; the return status is set to zero if all
STRINGs given as arguments are names of loaded modules and to
one if at least on STRING is not the name of a loaded module.
This can be used to test for the availability of things
implemented by modules. In this case, any aliases are
automatically resolved and the -A flag is not used.
zmodload -A [ -L ] [ MODALIAS[=MODULE] ... ]
For each argument, if both MODALIAS and MODULE are given,
define MODALIAS to be an alias for the module MODULE. If the
module MODALIAS is ever subsequently requested, either via a
call to zmodload or implicitly, the shell will attempt to load
MODULE instead. If MODULE is not given, show the definition
of MODALIAS. If no arguments are given, list all defined
module aliases. When listing, if the -L flag was also given,
list the definition as a zmodload command to recreate the
alias.
The existence of aliases for modules is completely
independent of whether the name resolved is actually loaded
as a module: while the alias exists, loading and unloading
the module under any alias has exactly the same effect as
using the resolved name, and does not affect the connection
between the alias and the resolved name which can be removed
either by zmodload -R or by redefining the alias. Chains of
aliases (i.e. where the first resolved name is itself an
alias) are valid so long as these are not circular. As the
aliases take the same format as module names, they may
include path separators: in this case, there is no
requirement for any part of the path named to exist as the
alias will be resolved first. For example, `any/old/alias'
is always a valid alias.
Dependencies added to aliased modules are actually added to
the resolved module; these remain if the alias is removed.
It is valid to create an alias whose name is one of the
standard shell modules and which resolves to a different
module. However, if a module has dependencies, it will not
be possible to use the module name as an alias as the module
will already be marked as a loadable module in its own right.
Apart from the above, aliases can be used in the zmodload
command anywhere module names are required. However, aliases
will not be shown in lists of loaded modules with a bare
`zmodload'.
zmodload -R MODALIAS ...
For each MODALIAS argument that was previously defined as a
module alias via zmodload -A, delete the alias. If any was
not defined, an error is caused and the remainder of the line
is ignored.
Note that zsh makes no distinction between modules that were linked
into the shell and modules that are loaded dynamically. In both
cases this builtin command has to be used to make available the
builtins and other things defined by modules (unless the module is
autoloaded on these definitions). This is true even for systems
that don't support dynamic loading of modules.
zparseopts
See *Note The zsh/zutil Module::.
zprof
See *Note The zsh/zprof Module::.
zpty
See *Note The zsh/zpty Module::.
zregexparse
See *Note The zsh/zutil Module::.
zsocket
See *Note The zsh/net/socket Module::.
zstyle
See *Note The zsh/zutil Module::.
ztcp
See *Note The zsh/net/tcp Module::.
File: zsh.info, Node: Zsh Line Editor, Next: Completion Widgets, Prev: Shell Builtin Commands, Up: Top
18 Zsh Line Editor
******************
18.1 Description
================
If the ZLE option is set (which it is by default in interactive shells)
and the shell input is attached to the terminal, the user is able to
edit command lines.
There are two display modes. The first, multiline mode, is the
default. It only works if the TERM parameter is set to a valid
terminal type that can move the cursor up. The second, single line
mode, is used if TERM is invalid or incapable of moving the cursor up,
or if the SINGLE_LINE_ZLE option is set. This mode is similar to
`ksh', and uses no termcap sequences. If TERM is "emacs", the ZLE
option will be unset by default.
The parameters BAUD, COLUMNS, and LINES are also used by the line
editor. *Note Parameters Used By The Shell::.
The parameter zle_highlight is also used by the line editor; *Note
Character Highlighting::. Highlighting of special characters and the
region between the cursor and the mark (as set with set-mark-command in
Emacs mode) is enabled by default; consult this reference for more
information. Irascible conservatives will wish to know that all
highlighting may be disabled by the following setting:
zle_highlight=(none)
* Menu:
* Keymaps::
* Zle Builtins::
* Zle Widgets::
* Character Highlighting::
File: zsh.info, Node: Keymaps, Next: Zle Builtins, Up: Zsh Line Editor
18.2 Keymaps
============
A keymap in ZLE contains a set of bindings between key sequences and
ZLE commands. The empty key sequence cannot be bound.
There can be any number of keymaps at any time, and each keymap has one
or more names. If all of a keymap's names are deleted, it disappears. bindkey
can be used to manipulate keymap names.
Initially, there are six keymaps:
emacs
EMACS emulation
viins
vi emulation - insert mode
vicmd
vi emulation - command mode
isearch
incremental search mode
command
read a command name
.safe
fallback keymap
The `.safe' keymap is special. It can never be altered, and the name
can never be removed. However, it can be linked to other names, which
can be removed. In the future other special keymaps may be added;
users should avoid using names beginning with `.' for their own keymaps.
In addition to these names, either `emacs' or `viins' is also linked to
the name `main'. If one of the VISUAL or EDITOR environment variables
contain the string `vi' when the shell starts up then it will be
`viins', otherwise it will be `emacs'. bindkey's -e and -v options
provide a convenient way to override this default choice.
When the editor starts up, it will select the `main' keymap. If that
keymap doesn't exist, it will use `.safe' instead.
In the `.safe' keymap, each single key is bound to self-insert, except
for ^J (line feed) and ^M (return) which are bound to accept-line.
This is deliberately not pleasant to use; if you are using it, it means
you deleted the main keymap, and you should put it back.
18.2.1 Reading Commands
-----------------------
When ZLE is reading a command from the terminal, it may read a sequence
that is bound to some command and is also a prefix of a longer bound
string. In this case ZLE will wait a certain time to see if more
characters are typed, and if not (or they don't match any longer
string) it will execute the binding. This timeout is defined by the
KEYTIMEOUT parameter; its default is 0.4 sec. There is no timeout if
the prefix string is not itself bound to a command.
The key timeout is also applied when ZLE is reading the bytes from a
multibyte character string when it is in the appropriate mode. (This
requires that the shell was compiled with multibyte mode enabled;
typically also the locale has characters with the UTF-8 encoding,
although any multibyte encoding known to the operating system is
supported.) If the second or a subsequent byte is not read within the
timeout period, the shell acts as if ? were typed and resets the input
state.
As well as ZLE commands, key sequences can be bound to other strings,
by using `bindkey -s'. When such a sequence is read, the replacement
string is pushed back as input, and the command reading process starts
again using these fake keystrokes. This input can itself invoke
further replacement strings, but in order to detect loops the process
will be stopped if there are twenty such replacements without a real
command being read.
A key sequence typed by the user can be turned into a command name for
use in user-defined widgets with the read-command widget, described in
*Note Miscellaneous:: below.
File: zsh.info, Node: Zle Builtins, Next: Zle Widgets, Prev: Keymaps, Up: Zsh Line Editor
18.3 Zle Builtins
=================
The ZLE module contains three related builtin commands. The bindkey
command manipulates keymaps and key bindings; the vared command invokes
ZLE on the value of a shell parameter; and the zle command manipulates
editing widgets and allows command line access to ZLE commands from
within shell functions.
bindkey [ OPTIONS ] -l
bindkey [ OPTIONS ] -d
bindkey [ OPTIONS ] -D KEYMAP ...
bindkey [ OPTIONS ] -A OLD-KEYMAP NEW-KEYMAP
bindkey [ OPTIONS ] -N NEW-KEYMAP [ OLD-KEYMAP ]
bindkey [ OPTIONS ] -m
bindkey [ OPTIONS ] -r IN-STRING ...
bindkey [ OPTIONS ] -s IN-STRING OUT-STRING ...
bindkey [ OPTIONS ] IN-STRING COMMAND ...
bindkey [ OPTIONS ] [ IN-STRING ]
bindkey's options can be divided into three categories: keymap
selection, operation selection, and others. The keymap selection
options are:
-e
Selects keymap `emacs', and also links it to `main'.
-v
Selects keymap `viins', and also links it to `main'.
-a
Selects keymap `vicmd'.
-M KEYMAP
The KEYMAP specifies a keymap name.
If a keymap selection is required and none of the options above
are used, the `main' keymap is used. Some operations do not
permit a keymap to be selected, namely:
-l
List all existing keymap names. If the -L option is also
used, list in the form of bindkey commands to create the
keymaps.
-d
Delete all existing keymaps and reset to the default state.
-D KEYMAP ...
Delete the named KEYMAPs.
-A OLD-KEYMAP NEW-KEYMAP
Make the NEW-KEYMAP name an alias for OLD-KEYMAP, so that
both names refer to the same keymap. The names have equal
standing; if either is deleted, the other remains. If there
is already a keymap with the NEW-KEYMAP name, it is deleted.
-N NEW-KEYMAP [ OLD-KEYMAP ]
Create a new keymap, named NEW-KEYMAP. If a keymap already
has that name, it is deleted. If an OLD-KEYMAP name is
given, the new keymap is initialized to be a duplicate of it,
otherwise the new keymap will be empty.
To use a newly created keymap, it should be linked to main. Hence
the sequence of commands to create and use a new keymap `mymap'
initialized from the emacs keymap (which remains unchanged) is:
bindkey -N mymap emacs
bindkey -A mymap main
Note that while `bindkey -A NEWMAP main' will work when NEWMAP is
emacs or viins, it will not work for vicmd, as switching from vi
insert to command mode becomes impossible.
The following operations act on the `main' keymap if no keymap
selection option was given:
-m
Add the built-in set of meta-key bindings to the selected
keymap. Only keys that are unbound or bound to self-insert
are affected.
-r IN-STRING ...
Unbind the specified IN-STRINGs in the selected keymap. This
is exactly equivalent to binding the strings to undefined-key.
When -R is also used, interpret the IN-STRINGs as ranges.
When -p is also used, the IN-STRINGs specify prefixes. Any
binding that has the given IN-STRING as a prefix, not
including the binding for the IN-STRING itself, if any, will
be removed. For example,
bindkey -rpM viins '^['
will remove all bindings in the vi-insert keymap beginning
with an escape character (probably cursor keys), but leave
the binding for the escape character itself (probably
vi-cmd-mode). This is incompatible with the option -R.
-s IN-STRING OUT-STRING ...
Bind each IN-STRING to each OUT-STRING. When IN-STRING is
typed, OUT-STRING will be pushed back and treated as input to
the line editor. When -R is also used, interpret the
IN-STRINGs as ranges.
IN-STRING COMMAND ...
Bind each IN-STRING to each COMMAND. When -R is used,
interpret the IN-STRINGs as ranges.
[ IN-STRING ]
List key bindings. If an IN-STRING is specified, the binding
of that string in the selected keymap is displayed.
Otherwise, all key bindings in the selected keymap are
displayed. (As a special case, if the -e or -v option is
used alone, the keymap is _not_ displayed - the implicit
linking of keymaps is the only thing that happens.)
When the option -p is used, the IN-STRING must be present.
The listing shows all bindings which have the given key
sequence as a prefix, not including any bindings for the key
sequence itself.
When the -L option is used, the list is in the form of bindkey
commands to create the key bindings.
When the -R option is used as noted above, a valid range consists
of two characters, with an optional `-' between them. All
characters between the two specified, inclusive, are bound as
specified.
For either IN-STRING or OUT-STRING, the following escape sequences
are recognised:
\a
bell character
\b
backspace
\e, \E
escape
\f
form feed
\n
linefeed (newline)
\r
carriage return
\t
horizontal tab
\v
vertical tab
\NNN
character code in octal
\xNN
character code in hexadecimal
\M[-]X
character with meta bit set
\C[-]X
control character
^X
control character
In all other cases, `\' escapes the following character. Delete is
written as `^?'. Note that `\M^?' and `^\M?' are not the same,
and that (unlike emacs), the bindings `\M-X' and `\eX' are
entirely distinct, although they are initialized to the same
bindings by `bindkey -m'.
vared [ -Aache ] [ -p PROMPT ] [ -r RPROMPT ]
[ -M MAIN-KEYMAP ] [ -m VICMD-KEYMAP ]
[ -t TTY ] NAME
The value of the parameter NAME is loaded into the edit buffer,
and the line editor is invoked. When the editor exits, NAME is
set to the string value returned by the editor. When the -c flag
is given, the parameter is created if it doesn't already exist.
The -a flag may be given with -c to create an array parameter, or
the -A flag to create an associative array. If the type of an
existing parameter does not match the type to be created, the
parameter is unset and recreated.
If an array or array slice is being edited, separator characters
as defined in $IFS will be shown quoted with a backslash, as will
backslashes themselves. Conversely, when the edited text is split
into an array, a backslash quotes an immediately following
separator character or backslash; no other special handling of
backslashes, or any handling of quotes, is performed.
Individual elements of existing array or associative array
parameters may be edited by using subscript syntax on NAME. New
elements are created automatically, even without -c.
If the -p flag is given, the following string will be taken as the
prompt to display at the left. If the -r flag is given, the
following string gives the prompt to display at the right. If the
-h flag is specified, the history can be accessed from ZLE. If the
-e flag is given, typing ^D (Control-D) on an empty line causes
vared to exit immediately with a non-zero return value.
The -M option gives a keymap to link to the main keymap during
editing, and the -m option gives a keymap to link to the vicmd
keymap during editing. For vi-style editing, this allows a pair
of keymaps to override viins and vicmd. For emacs-style editing,
only -M is normally needed but the -m option may still be used.
On exit, the previous keymaps will be restored.
If `-t TTY' is given, TTY is the name of a terminal device to be
used instead of the default /dev/tty. If TTY does not refer to a
terminal an error is reported.
zle
zle -l [ -L | -a ] [ STRING ... ]
zle -D WIDGET ...
zle -A OLD-WIDGET NEW-WIDGET
zle -N WIDGET [ FUNCTION ]
zle -C WIDGET COMPLETION-WIDGET FUNCTION
zle -R [ -c ] [ DISPLAY-STRING ] [ STRING ... ]
zle -M STRING
zle -U STRING
zle -K KEYMAP
zle -F [ -L ] [ FD [ HANDLER ] ]
zle -I
zle WIDGET [ -n NUM ] [ -Nw ] [ -K KEYMAP ] ARGS ...
The zle builtin performs a number of different actions concerning
ZLE.
With no options and no arguments, only the return status will be
set. It is zero if ZLE is currently active and widgets could be
invoked using this builtin command and non-zero otherwise. Note
that even if non-zero status is returned, zle may still be active
as part of the completion system; this does not allow direct calls
to ZLE widgets.
Otherwise, which operation it performs depends on its options:
-l [ -L | -a ]
List all existing user-defined widgets. If the -L option is
used, list in the form of zle commands to create the widgets.
When combined with the -a option, all widget names are listed,
including the builtin ones. In this case the -L option is
ignored.
If at least one STRING is given, nothing will be printed but
the return status will be zero if all STRINGs are names of
existing widgets (or of user-defined widgets if the -a flag
is not given) and non-zero if at least one STRING is not a
name of an defined widget.
-D WIDGET ...
Delete the named WIDGETs.
-A OLD-WIDGET NEW-WIDGET
Make the NEW-WIDGET name an alias for OLD-WIDGET, so that
both names refer to the same widget. The names have equal
standing; if either is deleted, the other remains. If there
is already a widget with the NEW-WIDGET name, it is deleted.
-N WIDGET [ FUNCTION ]
Create a user-defined widget. If there is already a widget
with the specified name, it is overwritten. When the new
widget is invoked from within the editor, the specified shell
FUNCTION is called. If no function name is specified, it
defaults to the same name as the widget. For further
information, see the section _Widgets_ in *Note Zsh Line
Editor::.
-C WIDGET COMPLETION-WIDGET FUNCTION
Create a user-defined completion widget named WIDGET. The
completion widget will behave like the built-in
completion-widget whose name is given as COMPLETION-WIDGET.
To generate the completions, the shell function FUNCTION will
be called. For further information, see *Note Completion
Widgets::.
-R [ -c ] [ DISPLAY-STRING ] [ STRING ... ]
Redisplay the command line; this is to be called from within
a user-defined widget to allow changes to become visible. If
a DISPLAY-STRING is given and not empty, this is shown in the
status line (immediately below the line being edited).
If the optional STRINGs are given they are listed below the
prompt in the same way as completion lists are printed. If no
STRINGs are given but the -c option is used such a list is
cleared.
Note that this option is only useful for widgets that do not
exit immediately after using it because the strings displayed
will be erased immediately after return from the widget.
This command can safely be called outside user defined
widgets; if zle is active, the display will be refreshed,
while if zle is not active, the command has no effect. In
this case there will usually be no other arguments.
The status is zero if zle was active, else one.
-M STRING
As with the -R option, the STRING will be displayed below the
command line; unlike the -R option, the string will not be
put into the status line but will instead be printed normally
below the prompt. This means that the STRING will still be
displayed after the widget returns (until it is overwritten
by subsequent commands).
-U STRING
This pushes the characters in the STRING onto the input stack
of ZLE. After the widget currently executed finishes ZLE
will behave as if the characters in the STRING were typed by
the user.
As ZLE uses a stack, if this option is used repeatedly the
last string pushed onto the stack will be processed first.
However, the characters in each STRING will be processed in
the order in which they appear in the string.
-K KEYMAP
Selects the keymap named KEYMAP. An error message will be
displayed if there is no such keymap.
This keymap selection affects the interpretation of following
keystrokes within this invocation of ZLE. Any following
invocation (e.g., the next command line) will start as usual
with the `main' keymap selected.
-F [ -L ] [ FD [ HANDLER ] ]
Only available if your system supports one of the `poll' or
`select' system calls; most modern systems do.
Installs HANDLER (the name of a shell function) to handle
input from file descriptor FD. When zle is attempting to
read data, it will examine both the terminal and the list of
handled FD's. If data becomes available on a handled FD, zle
will call HANDLER with the fd which is ready for reading as
the only argument. If the handler produces output to the
terminal, it should call `zle -I' before doing so (see
below). The handler should not attempt to read from the
terminal. Note that zle makes no attempt to check whether
this fd is actually readable when installing the handler.
The user must make their own arrangements for handling the
file descriptor when zle is not active.
Any number of handlers for any number of readable file
descriptors may be installed. Installing a handler for an FD
which is already handled causes the existing handler to be
replaced.
If no HANDLER is given, but an FD is present, any handler for
that FD is removed. If there is none, an error message is
printed and status 1 is returned.
If no arguments are given, or the -L option is supplied, a
list of handlers is printed in a form which can be stored for
later execution.
An FD (but not a HANDLER) may optionally be given with the -L
option; in this case, the function will list the handler if
any, else silently return status 1.
Note that this feature should be used with care. Activity on
one of the FD's which is not properly handled can cause the
terminal to become unusable.
Here is a simple example of using this feature. A connection
to a remote TCP port is created using the ztcp command; see
*Note The zsh/net/tcp Module::. Then a handler is installed
which simply prints out any data which arrives on this
connection. Note that `select' will indicate that the file
descriptor needs handling if the remote side has closed the
connection; we handle that by testing for a failed read.
if ztcp pwspc 2811; then
tcpfd=$REPLY
handler() {
zle -I
local line
if ! read -r line <&$1; then
# select marks this fd if we reach EOF,
# so handle this specially.
print "[Read on fd $1 failed, removing.]" >&2
zle -F $1
return 1
fi
print -r - $line
}
zle -F $tcpfd handler
fi
-I
Unusually, this option is most useful outside ordinary widget
functions, though it may be used within if normal output to
the terminal is required. It invalidates the current zle
display in preparation for output; typically this will be
from a trap function. It has no effect if zle is not active.
When a trap exits, the shell checks to see if the display
needs restoring, hence the following will print output in
such a way as not to disturb the line being edited:
TRAPUSR1() {
# Invalidate zle display
[[ -o zle ]] && zle -I
# Show output
print Hello
}
In general, the trap function may need to test whether zle is
active before using this method (as shown in the example),
since the zsh/zle module may not even be loaded; if it is
not, the command can be skipped.
It is possible to call `zle -I' several times before control
is returned to the editor; the display will only be
invalidated the first time to minimise disruption.
Note that there are normally better ways of manipulating the
display from within zle widgets; see, for example, `zle -R'
above.
The returned status is zero if zle was invalidated, even
though this may have been by a previous call to `zle -I' or
by a system notification. To test if a zle widget may be
called at this point, execute zle with no arguments and
examine the return status.
WIDGET [ -n NUM ] [ -Nw ] [ -K KEYMAP ] ARGS ...
Invoke the specified widget. This can only be done when ZLE
is active; normally this will be within a user-defined widget.
With the options -n and -N, the current numerical argument
will be saved and then restored after the call to widget; `-n
NUM' sets the numerical argument temporarily to NUM, while
`-N' sets it to the default, i.e. as if there were none.
With the option -K, KEYMAP will be used as the current keymap
during the execution of the widget. The previous keymap will
be restored when the widget exits.
Normally, calling a widget in this way does not set the
special parameter WIDGET and related parameters, so that the
environment appears as if the top-level widget called by the
user were still active. With the option -w, WIDGET and
related parameters are set to reflect the widget being
executed by the zle call.
Any further arguments will be passed to the widget; note that
as standard argument handling is performed, any general
argument list should be preceded by --. If it is a shell
function, these are passed down as positional parameters; for
builtin widgets it is up to the widget in question what it
does with them. Currently arguments are only handled by the
incremental-search commands, the history-search-forward and
-backward and the corresponding functions prefixed by vi-,
and by universal-argument. No error is flagged if the
command does not use the arguments, or only uses some of them.
The return status reflects the success or failure of the
operation carried out by the widget, or if it is a
user-defined widget the return status of the shell function.
A non-zero return status causes the shell to beep when the
widget exits, unless the BEEP options was unset or the widget
was called via the zle command. Thus if a user defined
widget requires an immediate beep, it should call the beep
widget directly.
File: zsh.info, Node: Zle Widgets, Next: Character Highlighting, Prev: Zle Builtins, Up: Zsh Line Editor
18.4 Widgets
============
All actions in the editor are performed by `widgets'. A widget's job is
simply to perform some small action. The ZLE commands that key
sequences in keymaps are bound to are in fact widgets. Widgets can be
user-defined or built in.
The standard widgets built in to ZLE are listed in Standard Widgets
below. Other built-in widgets can be defined by other modules (see
*Note Zsh Modules::). Each built-in widget has two names: its normal
canonical name, and the same name preceded by a `.'. The `.' name is
special: it can't be rebound to a different widget. This makes the
widget available even when its usual name has been redefined.
User-defined widgets are defined using `zle -N', and implemented as
shell functions. When the widget is executed, the corresponding shell
function is executed, and can perform editing (or other) actions. It
is recommended that user-defined widgets should not have names starting
with `.'.
18.5 User-Defined Widgets
=========================
User-defined widgets, being implemented as shell functions, can execute
any normal shell command. They can also run other widgets (whether
built-in or user-defined) using the zle builtin command. The standard
input of the function is closed to prevent external commands from
unintentionally blocking ZLE by reading from the terminal, but read -k
or read -q can be used to read characters. Finally, they can examine
and edit the ZLE buffer being edited by reading and setting the special
parameters described below.
These special parameters are always available in widget functions, but
are not in any way special outside ZLE. If they have some normal value
outside ZLE, that value is temporarily inaccessible, but will return
when the widget function exits. These special parameters in fact have
local scope, like parameters created in a function using local.
Inside completion widgets and traps called while ZLE is active, these
parameters are available read-only.
BUFFER (scalar)
The entire contents of the edit buffer. If it is written to, the
cursor remains at the same offset, unless that would put it
outside the buffer.
BUFFERLINES (integer)
The number of screen lines needed for the edit buffer currently
displayed on screen (i.e. without any changes to the preceding
parameters done after the last redisplay); read-only.
CONTEXT (scalar)
The context in which zle was called to read a line; read-only.
One of the values:
start
The start of a command line (at prompt PS1).
cont
A continuation to a command line (at prompt PS2).
select
In a select loop.
vared
Editing a variable in vared.
CURSOR (integer)
The offset of the cursor, within the edit buffer. This is in the
range 0 to $#BUFFER, and is by definition equal to $#LBUFFER.
Attempts to move the cursor outside the buffer will result in the
cursor being moved to the appropriate end of the buffer.
CUTBUFFER (scalar)
The last item to be cut using one of the `kill-' commands; the
string which the next yank would insert in the line. Later
entries in the kill ring are in the array killring. Note that the
command `zle copy-region-as-kill STRING' can be used to set the
text of the cut buffer from a shell function and cycle the kill
ring in the same way as interactively killing text.
HISTNO (integer)
The current history number. Setting this has the same effect as
moving up or down in the history to the corresponding history line.
An attempt to set it is ignored if the line is not stored in the
history. Note this is not the same as the parameter HISTCMD,
which always gives the number of the history line being added to
the main shell's history. HISTNO refers to the line being
retrieved within zle.
KEYMAP (scalar)
The name of the currently selected keymap; read-only.
KEYS (scalar)
The keys typed to invoke this widget, as a literal string;
read-only.
killring (array)
The array of previously killed items, with the most recently
killed first. This gives the items that would be retrieved by a
yank-pop in the same order. Note, however, that the most recently
killed item is in $CUTBUFFER; $killring shows the array of
previous entries.
The default size for the kill ring is eight, however the length
may be changed by normal array operations. Any empty string in
the kill ring is ignored by the yank-pop command, hence the size
of the array effectively sets the maximum length of the kill ring,
while the number of non-zero strings gives the current length,
both as seen by the user at the command line.
LASTABORTEDSEARCH (scalar)
The last search string used by an interactive search that was
aborted by the user (status 3 returned by the search widget).
LASTSEARCH (scalar)
The last search string used by an interactive search; read-only.
This is set even if the search failed (status 0, 1 or 2 returned
by the search widget), but not if it was aborted by the user.
LASTWIDGET (scalar)
The name of the last widget that was executed; read-only.
LBUFFER (scalar)
The part of the buffer that lies to the left of the cursor
position. If it is assigned to, only that part of the buffer is
replaced, and the cursor remains between the new $LBUFFER and the
old $RBUFFER.
MARK (integer)
Like CURSOR, but for the mark.
NUMERIC (integer)
The numeric argument. If no numeric argument was given, this
parameter is unset. When this is set inside a widget function,
builtin widgets called with the zle builtin command will use the
value assigned. If it is unset inside a widget function, builtin
widgets called behave as if no numeric argument was given.
PENDING (integer)
The number of bytes pending for input, i.e. the number of bytes
which have already been typed and can immediately be read. On
systems where the shell is not able to get this information, this
parameter will always have a value of zero. Read-only.
PREBUFFER (scalar)
In a multi-line input at the secondary prompt, this read-only
parameter contains the contents of the lines before the one the
cursor is currently in.
PREDISPLAY (scalar)
Text to be displayed before the start of the editable text buffer.
This does not have to be a complete line; to display a complete
line, a newline must be appended explicitly. The text is reset
on each new invocation (but not recursive invocation) of zle.
POSTDISPLAY (scalar)
Text to be displayed after the end of the editable text buffer.
This does not have to be a complete line; to display a complete
line, a newline must be prepended explicitly. The text is reset
on each new invocation (but not recursive invocation) of zle.
RBUFFER (scalar)
The part of the buffer that lies to the right of the cursor
position. If it is assigned to, only that part of the buffer is
replaced, and the cursor remains between the old $LBUFFER and the
new $RBUFFER.
REGION_ACTIVE (integer)
Indicates if the region is currently active. It can be assigned 0
or 1 to deactivate and activate the region respectively; *Note
Character Highlighting::.
region_highlight (array)
Each element of this array may be set to a string that describes
highlighting for an arbitrary region of the command line that will
take effect the next time the command line is redisplayed.
Highlighting of the non-editable parts of the command line in
PREDISPLAY and POSTDISPLAY are possible, but note that the P flag
is needed for character indexing to include PREDISPLAY.
Each string consists of the following parts:
Optionally, a `P' to signify that the start and end offset that
follow include any string set by the PREDISPLAY special
parameter; this is needed if the predisplay string itself is
to be highlighted. Whitespace may follow the `P'.
A start offset in the same units as CURSOR, terminated by
whitespace.
An end offset in the same units as CURSOR, terminated by
whitespace.
A highlight specification in the same format as
used for contexts in the parameter zle_highlight, *Note
Character Highlighting::; for example, standout or
fg=red,bold.
For example,
region_highlight=("P0 20 bold")
specifies that the first twenty characters of the text including
any predisplay string should be highlighted in bold.
Note that the effect of region_highlight is not saved and
disappears as soon as the line is accepted. The line editor makes
no attempt to keep the highlighting effect synchronised with the
line as it is edited; hence region highlighting is best limited to
static effects within user widgets.
WIDGET (scalar)
The name of the widget currently being executed; read-only.
WIDGETFUNC (scalar)
The name of the shell function that implements a widget defined
with either zle -N or zle -C. In the former case, this is the
second argument to the zle -N command that defined the widget, or
the first argument if there was no second argument. In the latter
case this is the the third argument to the zle -C command that
defined the widget. Read-only.
WIDGETSTYLE (scalar)
Describes the implementation behind the completion widget
currently being executed; the second argument that followed zle -C
when the widget was defined. This is the name of a builtin
completion widget. For widgets defined with zle -N this is set to
the empty string. Read-only.
18.5.1 Special Widgets
----------------------
There are a few user-defined widgets which are special to the shell.
If they do not exist, no special action is taken. The environment
provided is identical to that for any other editing widget.
zle-line-init
Executed every time the line editor is started to read a new line
of input. The following example puts the line editor into vi
command mode when it starts up.
zle-line-init() { zle -K vicmd; }
zle -N zle-line-init
(The command inside the function sets the keymap directly; it is
equivalent to zle vi-cmd-mode.)
zle-line-finish
This is similar to zle-line-init but is executed every time the
line editor has finished reading a line of input.
zle-keymap-select
Executed every time the keymap changes, i.e. the special parameter
KEYMAP is set to a different value, while the line editor is
active. Initialising the keymap when the line editor starts does
not cause the widget to be called.
The value $KEYMAP within the function reflects the new keymap. The
old keymap is passed as the sole argument.
This can been used for detecting switches between the vi command
(vicmd) and insert (usually main) keymaps.
18.6 Standard Widgets
=====================
The following is a list of all the standard widgets, and their default
bindings in emacs mode, vi command mode and vi insert mode (the
`emacs', `vicmd' and `viins' keymaps, respectively).
Note that cursor keys are bound to movement keys in all three keymaps;
the shell assumes that the cursor keys send the key sequences reported
by the terminal-handling library (termcap or terminfo). The key
sequences shown in the list are those based on the VT100, common on
many modern terminals, but in fact these are not necessarily bound. In
the case of the viins keymap, the initial escape character of the
sequences serves also to return to the vicmd keymap: whether this
happens is determined by the KEYTIMEOUT parameter, see *Note
Parameters::.
* Menu:
* Movement::
* History Control::
* Modifying Text::
* Arguments::
* Completion::
* Miscellaneous::
File: zsh.info, Node: Movement, Next: History Control, Up: Zle Widgets
18.6.1 Movement
---------------
vi-backward-blank-word (unbound) (B) (unbound)
Move backward one word, where a word is defined as a series of
non-blank characters.
backward-char (^B ESC-[D) (unbound) (unbound)
Move backward one character.
vi-backward-char (unbound) (^H h ^?) (ESC-[D)
Move backward one character, without changing lines.
backward-word (ESC-B ESC-b) (unbound) (unbound)
Move to the beginning of the previous word.
emacs-backward-word
Move to the beginning of the previous word.
vi-backward-word (unbound) (b) (unbound)
Move to the beginning of the previous word, vi-style.
beginning-of-line (^A) (unbound) (unbound)
Move to the beginning of the line. If already at the beginning of
the line, move to the beginning of the previous line, if any.
vi-beginning-of-line
Move to the beginning of the line, without changing lines.
end-of-line (^E) (unbound) (unbound)
Move to the end of the line. If already at the end of the line,
move to the end of the next line, if any.
vi-end-of-line (unbound) ($) (unbound)
Move to the end of the line. If an argument is given to this
command, the cursor will be moved to the end of the line (argument
- 1) lines down.
vi-forward-blank-word (unbound) (W) (unbound)
Move forward one word, where a word is defined as a series of
non-blank characters.
vi-forward-blank-word-end (unbound) (E) (unbound)
Move to the end of the current word, or, if at the end of the
current word, to the end of the next word, where a word is defined
as a series of non-blank characters.
forward-char (^F ESC-[C) (unbound) (unbound)
Move forward one character.
vi-forward-char (unbound) (space l) (ESC-[C)
Move forward one character.
vi-find-next-char (^X^F) (f) (unbound)
Read a character from the keyboard, and move to the next
occurrence of it in the line.
vi-find-next-char-skip (unbound) (t) (unbound)
Read a character from the keyboard, and move to the position just
before the next occurrence of it in the line.
vi-find-prev-char (unbound) (F) (unbound)
Read a character from the keyboard, and move to the previous
occurrence of it in the line.
vi-find-prev-char-skip (unbound) (T) (unbound)
Read a character from the keyboard, and move to the position just
after the previous occurrence of it in the line.
vi-first-non-blank (unbound) (^) (unbound)
Move to the first non-blank character in the line.
vi-forward-word (unbound) (w) (unbound)
Move forward one word, vi-style.
forward-word (ESC-F ESC-f) (unbound) (unbound)
Move to the beginning of the next word. The editor's idea of a
word is specified with the WORDCHARS parameter.
emacs-forward-word
Move to the end of the next word.
vi-forward-word-end (unbound) (e) (unbound)
Move to the end of the next word.
vi-goto-column (ESC-|) (|) (unbound)
Move to the column specified by the numeric argument.
vi-goto-mark (unbound) (`) (unbound)
Move to the specified mark.
vi-goto-mark-line (unbound) (') (unbound)
Move to beginning of the line containing the specified mark.
vi-repeat-find (unbound) (;) (unbound)
Repeat the last vi-find command.
vi-rev-repeat-find (unbound) (,) (unbound)
Repeat the last vi-find command in the opposite direction.
File: zsh.info, Node: History Control, Next: Modifying Text, Prev: Movement, Up: Zle Widgets
18.6.2 History Control
----------------------
beginning-of-buffer-or-history (ESC-<) (unbound) (unbound)
Move to the beginning of the buffer, or if already there, move to
the first event in the history list.
beginning-of-line-hist
Move to the beginning of the line. If already at the beginning of
the buffer, move to the previous history line.
beginning-of-history
Move to the first event in the history list.
down-line-or-history (^N ESC-[B) (j) (ESC-[B)
Move down a line in the buffer, or if already at the bottom line,
move to the next event in the history list.
vi-down-line-or-history (unbound) (+) (unbound)
Move down a line in the buffer, or if already at the bottom line,
move to the next event in the history list. Then move to the
first non-blank character on the line.
down-line-or-search
Move down a line in the buffer, or if already at the bottom line,
search forward in the history for a line beginning with the first
word in the buffer.
If called from a function by the zle command with arguments, the
first argument is taken as the string for which to search, rather
than the first word in the buffer.
down-history (unbound) (^N) (unbound)
Move to the next event in the history list.
history-beginning-search-backward
Search backward in the history for a line beginning with the
current line up to the cursor. This leaves the cursor in its
original position.
end-of-buffer-or-history (ESC->) (unbound) (unbound)
Move to the end of the buffer, or if already there, move to the
last event in the history list.
end-of-line-hist
Move to the end of the line. If already at the end of the buffer,
move to the next history line.
end-of-history
Move to the last event in the history list.
vi-fetch-history (unbound) (G) (unbound)
Fetch the history line specified by the numeric argument. This
defaults to the current history line (i.e. the one that isn't
history yet).
history-incremental-search-backward (^R ^Xr) (unbound) (unbound)
Search backward incrementally for a specified string. The search
is case-insensitive if the search string does not have uppercase
letters and no numeric argument was given. The string may begin
with `^' to anchor the search to the beginning of the line. When
called from a user-defined function returns the following
statuses: 0, if the search succeeded; 1, if the search failed; 2,
if the search term was a bad pattern; 3, if the search was aborted
by the send-break command.
A restricted set of editing functions is available in the
mini-buffer. Keys are looked up in the special isearch keymap,
and if not found there in the main keymap (note that by default
the isearch keymap is empty). An interrupt signal, as defined by
the stty setting, will stop the search and go back to the original
line. An undefined key will have the same effect. Note that the
following always perform the same task within incremental searches
and cannot be replaced by user defined widgets. The supported
functions are:
accept-and-hold
accept-and-infer-next-history
accept-line
accept-line-and-down-history
Perform the usual function after exiting incremental search.
The command line displayed is executed.
backward-delete-char
vi-backward-delete-char
Back up one place in the search history. If the search has
been repeated this does not immediately erase a character in
the minibuffer.
accept-search
Exit incremental search, retaining the command line but
performing no further action. Note that this function is not
bound by default and has no effect outside incremental search.
backward-delete-word
backward-kill-word
vi-backward-kill-word
Back up one character in the minibuffer; if multiple searches
have been performed since the character was inserted the
search history is rewound to the point just before the
character was entered. Hence this has the effect of repeating
backward-delete-char.
clear-screen
Clear the screen, remaining in incremental search mode.
history-incremental-search-backward
Find the next occurrence of the contents of the mini-buffer.
history-incremental-search-forward
Invert the sense of the search.
magic-space
Inserts a non-magical space.
quoted-insert
vi-quoted-insert
Quote the character to insert into the minibuffer.
redisplay
Redisplay the command line, remaining in incremental search
mode.
vi-cmd-mode
Toggle between the `main' and `vicmd' keymaps; the `main'
keymap (insert mode) will be selected initially.
vi-repeat-search
vi-rev-repeat-search
Repeat the search. The direction of the search is indicated
in the mini-buffer.
Any multi-character string that is not bound to one of the above
functions will beep and interrupt the search, leaving the last
found line in the buffer. Any single character that is not bound
to one of the above functions, or self-insert or
self-insert-unmeta, will have the same effect but the function
will be executed.
When called from a widget function by the zle command, the
incremental search commands can take a string argument. This will
be treated as a string of keys, as for arguments to the bindkey
command, and used as initial input for the command. Any
characters in the string which are unused by the incremental
search will be silently ignored. For example,
zle history-incremental-search-backward forceps
will search backwards for forceps, leaving the minibuffer
containing the string `forceps'.
history-incremental-search-forward (^S ^Xs) (unbound) (unbound)
Search forward incrementally for a specified string. The search is
case-insensitive if the search string does not have uppercase
letters and no numeric argument was given. The string may begin
with `^' to anchor the search to the beginning of the line. The
functions available in the mini-buffer are the same as for
history-incremental-search-backward.
history-incremental-pattern-search-backward
history-incremental-pattern-search-forward
These widgets behave similarly to the corresponding widgets with
no -pattern, but the search string typed by the user is treated as
a pattern, respecting the current settings of the various options
affecting pattern matching. See *Note Filename Generation:: for a
description of patterns. If no numeric argument was given
lowercase letters in the search string may match uppercase letters
in the history. The string may begin with `^' to anchor the
search to the beginning of the line.
The prompt changes to indicate an invalid pattern; this may simply
indicate the pattern is not yet complete.
Note that only non-overlapping matches are reported, so an
expression with wildcards may return fewer matches on a line than
are visible by inspection.
history-search-backward (ESC-P ESC-p) (unbound) (unbound)
Search backward in the history for a line beginning with the first
word in the buffer.
If called from a function by the zle command with arguments, the
first argument is taken as the string for which to search, rather
than the first word in the buffer.
vi-history-search-backward (unbound) (/) (unbound)
Search backward in the history for a specified string. The string
may begin with `^' to anchor the search to the beginning of the
line.
A restricted set of editing functions is available in the
mini-buffer. An interrupt signal, as defined by the stty setting,
will stop the search. The functions available in the mini-buffer
are: accept-line, backward-delete-char, vi-backward-delete-char,
backward-kill-word, vi-backward-kill-word, clear-screen, redisplay,
quoted-insert and vi-quoted-insert.
vi-cmd-mode is treated the same as accept-line, and magic-space is
treated as a space. Any other character that is not bound to
self-insert or self-insert-unmeta will beep and be ignored. If the
function is called from vi command mode, the bindings of the
current insert mode will be used.
If called from a function by the zle command with arguments, the
first argument is taken as the string for which to search, rather
than the first word in the buffer.
history-search-forward (ESC-N ESC-n) (unbound) (unbound)
Search forward in the history for a line beginning with the first
word in the buffer.
If called from a function by the zle command with arguments, the
first argument is taken as the string for which to search, rather
than the first word in the buffer.
vi-history-search-forward (unbound) (?) (unbound)
Search forward in the history for a specified string. The string
may begin with `^' to anchor the search to the beginning of the
line. The functions available in the mini-buffer are the same as
for vi-history-search-backward. Argument handling is also the same
as for that command.
infer-next-history (^X^N) (unbound) (unbound)
Search in the history list for a line matching the current one and
fetch the event following it.
insert-last-word (ESC-_ ESC-.) (unbound) (unbound)
Insert the last word from the previous history event at the cursor
position. If a positive numeric argument is given, insert that
word from the end of the previous history event. If the argument
is zero or negative insert that word from the left (zero inserts
the previous command word). Repeating this command replaces the
word just inserted with the last word from the history event prior
to the one just used; numeric arguments can be used in the same
way to pick a word from that event.
When called from a shell function invoked from a user-defined
widget, the command can take one to three arguments. The first
argument specifies a history offset which applies to successive
calls to this widget: if is -1, the default behaviour is used,
while if it is 1, successive calls will move forwards through the
history. The value 0 can be used to indicate that the history
line examined by the previous execution of the command will be
reexamined. Note that negative numbers should be preceded with a
`--' argument to avoid confusing them with options.
If two arguments are given, the second specifies the word on the
command line in normal array index notation (as a more natural
alternative to the prefix argument). Hence 1 is the first word,
and -1 (the default) is the last word.
If a third argument is given, its value is ignored, but it is used
to signify that the history offset is relative to the current
history line, rather than the one remembered after the previous
invocations of insert-last-word.
For example, the default behaviour of the command corresponds to
zle insert-last-word -- -1 -1
while the command
zle insert-last-word -- -1 1 -
always copies the first word of the line in the history
immediately before the line being edited. This has the side
effect that later invocations of the widget will be relative to
that line.
vi-repeat-search (unbound) (n) (unbound)
Repeat the last vi history search.
vi-rev-repeat-search (unbound) (N) (unbound)
Repeat the last vi history search, but in reverse.
up-line-or-history (^P ESC-[A) (k) (ESC-[A)
Move up a line in the buffer, or if already at the top line, move
to the previous event in the history list.
vi-up-line-or-history (unbound) (-) (unbound)
Move up a line in the buffer, or if already at the top line, move
to the previous event in the history list. Then move to the first
non-blank character on the line.
up-line-or-search
Move up a line in the buffer, or if already at the top line,
search backward in the history for a line beginning with the first
word in the buffer.
If called from a function by the zle command with arguments, the
first argument is taken as the string for which to search, rather
than the first word in the buffer.
up-history (unbound) (^P) (unbound)
Move to the previous event in the history list.
history-beginning-search-forward
Search forward in the history for a line beginning with the current
line up to the cursor. This leaves the cursor in its original
position.
File: zsh.info, Node: Modifying Text, Next: Arguments, Prev: History Control, Up: Zle Widgets
18.6.3 Modifying Text
---------------------
vi-add-eol (unbound) (A) (unbound)
Move to the end of the line and enter insert mode.
vi-add-next (unbound) (a) (unbound)
Enter insert mode after the current cursor position, without
changing lines.
backward-delete-char (^H ^?) (unbound) (unbound)
Delete the character behind the cursor.
vi-backward-delete-char (unbound) (X) (^H)
Delete the character behind the cursor, without changing lines.
If in insert mode, this won't delete past the point where insert
mode was last entered.
backward-delete-word
Delete the word behind the cursor.
backward-kill-line
Kill from the beginning of the line to the cursor position.
backward-kill-word (^W ESC-^H ESC-^?) (unbound) (unbound)
Kill the word behind the cursor.
vi-backward-kill-word (unbound) (unbound) (^W)
Kill the word behind the cursor, without going past the point
where insert mode was last entered.
capitalize-word (ESC-C ESC-c) (unbound) (unbound)
Capitalize the current word and move past it.
vi-change (unbound) (c) (unbound)
Read a movement command from the keyboard, and kill from the
cursor position to the endpoint of the movement. Then enter
insert mode. If the command is vi-change, change the current line.
vi-change-eol (unbound) (C) (unbound)
Kill to the end of the line and enter insert mode.
vi-change-whole-line (unbound) (S) (unbound)
Kill the current line and enter insert mode.
copy-region-as-kill (ESC-W ESC-w) (unbound) (unbound)
Copy the area from the cursor to the mark to the kill buffer.
If called from a ZLE widget function in the form `zle
copy-region-as-kill STRING' then STRING will be taken as the text
to copy to the kill buffer. The cursor, the mark and the text on
the command line are not used in this case.
copy-prev-word (ESC-^_) (unbound) (unbound)
Duplicate the word to the left of the cursor.
copy-prev-shell-word
Like copy-prev-word, but the word is found by using shell parsing,
whereas copy-prev-word looks for blanks. This makes a difference
when the word is quoted and contains spaces.
vi-delete (unbound) (d) (unbound)
Read a movement command from the keyboard, and kill from the
cursor position to the endpoint of the movement. If the command
is vi-delete, kill the current line.
delete-char
Delete the character under the cursor.
vi-delete-char (unbound) (x) (unbound)
Delete the character under the cursor, without going past the end
of the line.
delete-word
Delete the current word.
down-case-word (ESC-L ESC-l) (unbound) (unbound)
Convert the current word to all lowercase and move past it.
kill-word (ESC-D ESC-d) (unbound) (unbound)
Kill the current word.
gosmacs-transpose-chars
Exchange the two characters behind the cursor.
vi-indent (unbound) (>) (unbound)
Indent a number of lines.
vi-insert (unbound) (i) (unbound)
Enter insert mode.
vi-insert-bol (unbound) (I) (unbound)
Move to the first non-blank character on the line and enter insert
mode.
vi-join (^X^J) (J) (unbound)
Join the current line with the next one.
kill-line (^K) (unbound) (unbound)
Kill from the cursor to the end of the line. If already on the
end of the line, kill the newline character.
vi-kill-line (unbound) (unbound) (^U)
Kill from the cursor back to wherever insert mode was last entered.
vi-kill-eol (unbound) (D) (unbound)
Kill from the cursor to the end of the line.
kill-region
Kill from the cursor to the mark.
kill-buffer (^X^K) (unbound) (unbound)
Kill the entire buffer.
kill-whole-line (^U) (unbound) (unbound)
Kill the current line.
vi-match-bracket (^X^B) (%) (unbound)
Move to the bracket character (one of {}, () or []) that matches
the one under the cursor. If the cursor is not on a bracket
character, move forward without going past the end of the line to
find one, and then go to the matching bracket.
vi-open-line-above (unbound) (O) (unbound)
Open a line above the cursor and enter insert mode.
vi-open-line-below (unbound) (o) (unbound)
Open a line below the cursor and enter insert mode.
vi-oper-swap-case
Read a movement command from the keyboard, and swap the case of
all characters from the cursor position to the endpoint of the
movement. If the movement command is vi-oper-swap-case, swap the
case of all characters on the current line.
overwrite-mode (^X^O) (unbound) (unbound)
Toggle between overwrite mode and insert mode.
vi-put-before (unbound) (P) (unbound)
Insert the contents of the kill buffer before the cursor. If the
kill buffer contains a sequence of lines (as opposed to
characters), paste it above the current line.
vi-put-after (unbound) (p) (unbound)
Insert the contents of the kill buffer after the cursor. If the
kill buffer contains a sequence of lines (as opposed to
characters), paste it below the current line.
quoted-insert (^V) (unbound) (unbound)
Insert the next character typed into the buffer literally. An
interrupt character will not be inserted.
vi-quoted-insert (unbound) (unbound) (^Q ^V)
Display a `^' at the cursor position, and insert the next
character typed into the buffer literally. An interrupt character
will not be inserted.
quote-line (ESC-') (unbound) (unbound)
Quote the current line; that is, put a `'' character at the
beginning and the end, and convert all `'' characters to `'\'''.
quote-region (ESC-") (unbound) (unbound)
Quote the region from the cursor to the mark.
vi-replace (unbound) (R) (unbound)
Enter overwrite mode.
vi-repeat-change (unbound) (.) (unbound)
Repeat the last vi mode text modification. If a count was used
with the modification, it is remembered. If a count is given to
this command, it overrides the remembered count, and is remembered
for future uses of this command. The cut buffer specification is
similarly remembered.
vi-replace-chars (unbound) (r) (unbound)
Replace the character under the cursor with a character read from
the keyboard.
self-insert (printable characters) (unbound) (printable characters and some control characters)
Insert a character into the buffer at the cursor position.
self-insert-unmeta (ESC-^I ESC-^J ESC-^M) (unbound) (unbound)
Insert a character into the buffer after stripping the meta bit
and converting ^M to ^J.
vi-substitute (unbound) (s) (unbound)
Substitute the next character(s).
vi-swap-case (unbound) (~) (unbound)
Swap the case of the character under the cursor and move past it.
transpose-chars (^T) (unbound) (unbound)
Exchange the two characters to the left of the cursor if at end of
line, else exchange the character under the cursor with the
character to the left.
transpose-words (ESC-T ESC-t) (unbound) (unbound)
Exchange the current word with the one before it.
vi-unindent (unbound) (<) (unbound)
Unindent a number of lines.
up-case-word (ESC-U ESC-u) (unbound) (unbound)
Convert the current word to all caps and move past it.
yank (^Y) (unbound) (unbound)
Insert the contents of the kill buffer at the cursor position.
yank-pop (ESC-y) (unbound) (unbound)
Remove the text just yanked, rotate the kill-ring (the history of
previously killed text) and yank the new top. Only works following
yank or yank-pop.
vi-yank (unbound) (y) (unbound)
Read a movement command from the keyboard, and copy the region
from the cursor position to the endpoint of the movement into the
kill buffer. If the command is vi-yank, copy the current line.
vi-yank-whole-line (unbound) (Y) (unbound)
Copy the current line into the kill buffer.
vi-yank-eol
Copy the region from the cursor position to the end of the line
into the kill buffer. Arguably, this is what Y should do in vi,
but it isn't what it actually does.
File: zsh.info, Node: Arguments, Next: Completion, Prev: Modifying Text, Up: Zle Widgets
18.6.4 Arguments
----------------
digit-argument (ESC-0..ESC-9) (1-9) (unbound)
Start a new numeric argument, or add to the current one. See also
vi-digit-or-beginning-of-line. This only works if bound to a key
sequence ending in a decimal digit.
Inside a widget function, a call to this function treats the last
key of the key sequence which called the widget as the digit.
neg-argument (ESC--) (unbound) (unbound)
Changes the sign of the following argument.
universal-argument
Multiply the argument of the next command by 4. Alternatively, if
this command is followed by an integer (positive or negative), use
that as the argument for the next command. Thus digits cannot be
repeated using this command. For example, if this command occurs
twice, followed immediately by forward-char, move forward sixteen
spaces; if instead it is followed by -2, then forward-char, move
backward two spaces.
Inside a widget function, if passed an argument, i.e. `zle
universal-argument NUM', the numerical argument will be set to
NUM; this is equivalent to `NUMERIC=NUM'.
argument-base
Use the existing numeric argument as a numeric base, which must be
in the range 2 to 36 inclusive. Subsequent use of digit-argument
and universal-argument will input a new prefix in the given base.
The usual hexadecimal convention is used: the letter a or A
corresponds to 10, and so on. Arguments in bases requiring digits
from 10 upwards are more conveniently input with
universal-argument, since ESC-a etc. are not usually bound to
digit-argument.
The function can be used with a command argument inside a
user-defined widget. The following code sets the base to 16 and
lets the user input a hexadecimal argument until a key out of the
digit range is typed:
zle argument-base 16
zle universal-argument
File: zsh.info, Node: Completion, Next: Miscellaneous, Prev: Arguments, Up: Zle Widgets
18.6.5 Completion
-----------------
accept-and-menu-complete
In a menu completion, insert the current completion into the
buffer, and advance to the next possible completion.
complete-word
Attempt completion on the current word.
delete-char-or-list (^D) (unbound) (unbound)
Delete the character under the cursor. If the cursor is at the
end of the line, list possible completions for the current word.
expand-cmd-path
Expand the current command to its full pathname.
expand-or-complete (TAB) (unbound) (TAB)
Attempt shell expansion on the current word. If that fails,
attempt completion.
expand-or-complete-prefix
Attempt shell expansion on the current word up to cursor.
expand-history (ESC-space ESC-!) (unbound) (unbound)
Perform history expansion on the edit buffer.
expand-word (^X*) (unbound) (unbound)
Attempt shell expansion on the current word.
list-choices (ESC-^D) (^D =) (^D)
List possible completions for the current word.
list-expand (^Xg ^XG) (^G) (^G)
List the expansion of the current word.
magic-space
Perform history expansion and insert a space into the buffer.
This is intended to be bound to space.
menu-complete
Like complete-word, except that menu completion is used. See the
MENU_COMPLETE option.
menu-expand-or-complete
Like expand-or-complete, except that menu completion is used.
reverse-menu-complete
Perform menu completion, like menu-complete, except that if a menu
completion is already in progress, move to the _previous_
completion rather than the next.
end-of-list
When a previous completion displayed a list below the prompt, this
widget can be used to move the prompt below the list.
File: zsh.info, Node: Miscellaneous, Prev: Completion, Up: Zle Widgets
18.6.6 Miscellaneous
--------------------
accept-and-hold (ESC-A ESC-a) (unbound) (unbound)
Push the contents of the buffer on the buffer stack and execute it.
accept-and-infer-next-history
Execute the contents of the buffer. Then search the history list
for a line matching the current one and push the event following
onto the buffer stack.
accept-line (^J ^M) (^J ^M) (^J ^M)
Finish editing the buffer. Normally this causes the buffer to be
executed as a shell command.
accept-line-and-down-history (^O) (unbound) (unbound)
Execute the current line, and push the next history event on the
the buffer stack.
auto-suffix-remove
If the previous action added a suffix (space, slash, etc.) to the
word on the command line, remove it. Otherwise do nothing.
Removing the suffix ends any active menu completion or menu
selection.
This widget is intended to be called from user-defined widgets to
enforce a desired suffix-removal behavior.
auto-suffix-retain
If the previous action added a suffix (space, slash, etc.) to the
word on the command line, force it to be preserved. Otherwise do
nothing. Retaining the suffix ends any active menu completion or
menu selection.
This widget is intended to be called from user-defined widgets to
enforce a desired suffix-preservation behavior.
beep
Beep, unless the BEEP option is unset.
vi-cmd-mode (^X^V) (unbound) (^[)
Enter command mode; that is, select the `vicmd' keymap. Yes, this
is bound by default in emacs mode.
vi-caps-lock-panic
Hang until any lowercase key is pressed. This is for vi users
without the mental capacity to keep track of their caps lock key
(like the author).
clear-screen (^L ESC-^L) (^L) (^L)
Clear the screen and redraw the prompt.
describe-key-briefly
Reads a key sequence, then prints the function bound to that
sequence.
exchange-point-and-mark (^X^X) (unbound) (unbound)
Exchange the cursor position (point) with the position of the mark.
Unless a negative prefix argument is given, the region between
point and mark is activated so that it can be highlighted. If a
zero prefix argument is given, the region is activated but point
and mark are not swapped.
execute-named-cmd (ESC-x) (:) (unbound)
Read the name of an editor command and execute it. A restricted
set of editing functions is available in the mini-buffer. Keys
are looked up in the special command keymap, and if not found
there in the main keymap. An interrupt signal, as defined by the
stty setting, will abort the function. The allowed functions are:
backward-delete-char, vi-backward-delete-char, clear-screen,
redisplay, quoted-insert, vi-quoted-insert, backward-kill-word,
vi-backward-kill-word, kill-whole-line, vi-kill-line,
backward-kill-line, list-choices, delete-char-or-list,
complete-word, accept-line, expand-or-complete and
expand-or-complete-prefix.
kill-region kills the last word, and vi-cmd-mode is treated the
same as accept-line. The space and tab characters, if not bound
to one of these functions, will complete the name and then list the
possibilities if the AUTO_LIST option is set. Any other character
that is not bound to self-insert or self-insert-unmeta will beep
and be ignored. The bindings of the current insert mode will be
used.
Currently this command may not be redefined or called by name.
execute-last-named-cmd (ESC-z) (unbound) (unbound)
Redo the last function executed with execute-named-cmd.
Currently this command may not be redefined or called by name.
get-line (ESC-G ESC-g) (unbound) (unbound)
Pop the top line off the buffer stack and insert it at the cursor
position.
pound-insert (unbound) (#) (unbound)
If there is no # character at the beginning of the buffer, add one
to the beginning of each line. If there is one, remove a # from
each line that has one. In either case, accept the current line.
The INTERACTIVE_COMMENTS option must be set for this to have any
usefulness.
vi-pound-insert
If there is no # character at the beginning of the current line,
add one. If there is one, remove it. The INTERACTIVE_COMMENTS
option must be set for this to have any usefulness.
push-input
Push the entire current multiline construct onto the buffer stack
and return to the top-level (PS1) prompt. If the current parser
construct is only a single line, this is exactly like push-line.
Next time the editor starts up or is popped with get-line, the
construct will be popped off the top of the buffer stack and loaded
into the editing buffer.
push-line (^Q ESC-Q ESC-q) (unbound) (unbound)
Push the current buffer onto the buffer stack and clear the buffer.
Next time the editor starts up, the buffer will be popped off the
top of the buffer stack and loaded into the editing buffer.
push-line-or-edit
At the top-level (PS1) prompt, equivalent to push-line. At a
secondary (PS2) prompt, move the entire current multiline
construct into the editor buffer. The latter is equivalent to
push-input followed by get-line.
read-command
Only useful from a user-defined widget. A keystroke is read just
as in normal operation, but instead of the command being executed
the name of the command that would be executed is stored in the
shell parameter REPLY. This can be used as the argument of a
future zle command. If the key sequence is not bound, status 1 is
returned; typically, however, REPLY is set to undefined-key to
indicate a useless key sequence.
recursive-edit
Only useful from a user-defined widget. At this point in the
function, the editor regains control until one of the standard
widgets which would normally cause zle to exit (typically an
accept-line caused by hitting the return key) is executed.
Instead, control returns to the user-defined widget. The status
returned is non-zero if the return was caused by an error, but the
function still continues executing and hence may tidy up. This
makes it safe for the user-defined widget to alter the command
line or key bindings temporarily.
The following widget, caps-lock, serves as an example.
self-insert-ucase() {
LBUFFER+=${(U)KEYS[-1]}
}
integer stat
zle -N self-insert self-insert-ucase
zle -A caps-lock save-caps-lock
zle -A accept-line caps-lock
zle recursive-edit
stat=$?
zle -A .self-insert self-insert
zle -A save-caps-lock caps-lock
zle -D save-caps-lock
(( stat )) && zle send-break
return $stat
This causes typed letters to be inserted capitalised until either
accept-line (i.e. typically the return key) is typed or the
caps-lock widget is invoked again; the later is handled by saving
the old definition of caps-lock as save-caps-lock and then
rebinding it to invoke accept-line. Note that an error from the
recursive edit is detected as a non-zero return status and
propagated by using the send-break widget.
redisplay (unbound) (^R) (^R)
Redisplays the edit buffer.
reset-prompt (unbound) (unbound) (unbound)
Force the prompts on both the left and right of the screen to be
re-expanded, then redisplay the edit buffer. This reflects
changes both to the prompt variables themselves and changes in the
expansion of the values (for example, changes in time or
directory, or changes to the value of variables referred to by the
prompt).
Otherwise, the prompt is only expanded each time zle starts, and
when the display as been interrupted by output from another part
of the shell (such as a job notification) which causes the command
line to be reprinted.
send-break (^G ESC-^G) (unbound) (unbound)
Abort the current editor function, e.g. execute-named-command, or
the editor itself, e.g. if you are in vared. Otherwise abort the
parsing of the current line.
run-help (ESC-H ESC-h) (unbound) (unbound)
Push the buffer onto the buffer stack, and execute the command
`run-help CMD', where CMD is the current command. run-help is
normally aliased to man.
vi-set-buffer (unbound) (") (unbound)
Specify a buffer to be used in the following command. There are
35 buffers that can be specified: the 26 `named' buffers "a to "z
and the nine `queued' buffers "1 to "9. The named buffers can also
be specified as "A to "Z.
When a buffer is specified for a cut command, the text being cut
replaces the previous contents of the specified buffer. If a
named buffer is specified using a capital, the newly cut text is
appended to the buffer instead of overwriting it.
If no buffer is specified for a cut command, "1 is used, and the
contents of "1 to "8 are each shifted along one buffer; the
contents of "9 is lost.
vi-set-mark (unbound) (m) (unbound)
Set the specified mark at the cursor position.
set-mark-command (^@) (unbound) (unbound)
Set the mark at the cursor position. If called with a negative
prefix argument, do not set the mark but deactivate the region so
that it is no longer highlighted (it is still usable for other
purposes). Otherwise the region is marked as active.
spell-word (ESC-$ ESC-S ESC-s) (unbound) (unbound)
Attempt spelling correction on the current word.
undefined-key
This command is executed when a key sequence that is not bound to
any command is typed. By default it beeps.
undo (^_ ^Xu ^X^U) (unbound) (unbound)
Incrementally undo the last text modification.
redo
Incrementally redo undone text modifications.
vi-undo-change (unbound) (u) (unbound)
Undo the last text modification. If repeated, redo the
modification.
what-cursor-position (^X=) (unbound) (unbound)
Print the character under the cursor, its code as an octal,
decimal and hexadecimal number, the current cursor position within
the buffer and the column of the cursor in the current line.
where-is
Read the name of an editor command and and print the listing of key
sequences that invoke the specified command. A restricted set of
editing functions is available in the mini-buffer. Keys are
looked up in the special command keymap, and if not found there in
the main keymap.
which-command (ESC-?) (unbound) (unbound)
Push the buffer onto the buffer stack, and execute the command
`which-command CMD'. where CMD is the current command.
which-command is normally aliased to WHENCE.
vi-digit-or-beginning-of-line (unbound) (0) (unbound)
If the last command executed was a digit as part of an argument,
continue the argument. Otherwise, execute vi-beginning-of-line.
File: zsh.info, Node: Character Highlighting, Prev: Zle Widgets, Up: Zsh Line Editor
18.7 Character Highlighting
===========================
The line editor has the ability to highlight characters or regions of
the line that have a particular significance. This is controlled by
the array parameter zle_highlight, if it has been set by the user.
If the parameter contains the single entry none all highlighting is
turned off. Note the parameter is still expected to be an array.
Otherwise each entry of the array should consist of a word indicating a
context for highlighting, then a colon, then a comma-separated list of
the types of highlighting to apply in that context.
The contexts available for highlighting are the following:
default
Any text within the command line not affected by any other
highlighting. Text outside the editable area of the command line
is not affected.
isearch
When one of the incremental history search widgets is active, the
area of the command line matched by the search string or pattern.
region
The region between the cursor (point) and the mark as set with
set-mark-command. The region is only highlighted if it is active,
which is the case if set-mark-command or exchange-point-and-mark
has been called and the line has not been subsequently modified.
The region can be deactivated by calling set-mark-command with a
negative prefix argument, or reactivated by calling
exchange-point-and-mark with a zero prefix argument. Note that
whether or not the region is active has no effect on its use
within widgets, it simply determines whether it is highlighted.
special
Individual characters that have no direct printable representation
but are shown in a special manner by the line editor. These
characters are described below.
zle_highlight may contain additional fields for controlling how
terminal sequences to change colours are output. Each of the following
is followed by a colon and a string in the same form as for key
bindings. This will not be necessary for the vast majority of
terminals as the defaults shown in parentheses are widely used.
fg_start_code (\e[3)
The start of the escape sequence for the foreground colour. This
is followed by an ASCII digit representing the colour.
fg_default_code (9)
The number to use instead of the colour to reset the default
foreground colour.
fg_end_code (m)
The end of the escape sequence for the foreground colour.
bg_start_code (\e[4)
The start of the escape sequence for the background colour. This
is followed by an ASCII digit representing the colour.
bg_default_code (9)
The number to use instead of the colour to reset the default
background colour.
bg_end_code (m)
The end of the escape sequence for the background colour.
The available types of highlighting are the following. Note that not
all types of highlighting are available on all terminals:
none
No highlighting is applied to the given context. It is not useful
for this to appear with other types of highlighting; it is used to
override a default.
fg=COLOUR
The foreground colour should be set to COLOUR, a decimal integer
or the name of one of the eight most widely-supported colours.
Not all terminals support this and, of those that do, not all
provide facilities to test the support, hence the user should
decide based on the terminal type. Most terminals support the
colours black, red, green, yellow, blue, magenta, cyan and white,
which can be set by name. In addition. default may be used to set
the terminal's default foreground colour. Abbreviations are
allowed; b or bl selects black. Some terminals may generate
additional colours if the bold attribute is also present.
On recent terminals and on systems with an up-to-date terminal
database the number of colours supported may be tested by the
command `echotc Co'; if this succeeds, it indicates a limit on the
number of colours which will be enforced by the line editor. The
number of colours is in any case limited to 256 (i.e. the range 0
to 255).
Colour is also known as color.
bg=COLOUR
The background colour should be set to COLOUR. This works
similarly to the foreground colour, except the background is not
usually affected by the bold attribute.
bold
The characters in the given context are shown in a bold font.
standout
The characters in the given context are shown in the terminal's
standout mode. The actual effect is specific to the terminal; on
many terminals it is inverse video. On some such terminals, where
the cursor does not blink it appears with standout mode negated,
making it less than clear where the cursor actually is. On such
terminals one of the other effects may be preferable for
highlighting the region and matched search string.
underline
The characters in the given context are shown underlined. Some
terminals show the foreground in a different colour instead; in
this case whitespace will not be highlighted.
The characters described above as `special' are as follows. The
formatting described here is used irrespective of whether the characters
are highlighted:
ASCII control characters
Control characters in the ASCII range are shown as `^' followed by
the base character.
Unprintable multibyte characters
This item applies to control characters not in the ASCII range,
plus other characters as follows. If the MULTIBYTE option is in
effect, multibyte characters not in the ASCII character set that
are reported as having zero width are treated as combining
characters when the option COMBINING_CHARS is on. If the option
is off, or if a character appears where a combining character is
not valid, the character is treated as unprintable.
Unprintable multibyte characters are shown as a hexadecimal number
between angle brackets. The number is the code point of the
character in the wide character set; this may or may not be
Unicode, depending on the operating system.
If zle_highlight is not set or no value applies to a particular
context, the defaults applied are equivalent to
zle_highlight=(region:standout special:standout
isearch:underline)
i.e. both the region and special characters are shown in standout mode.
Within widgets, arbitrary regions may be highlighted by setting the
special array parameter region_highlight; see *Note Zle Widgets::.
File: zsh.info, Node: Completion Widgets, Next: Completion System, Prev: Zsh Line Editor, Up: Top
19 Completion Widgets
*********************
19.1 Description
================
The shell's programmable completion mechanism can be manipulated in two
ways; here the low-level features supporting the newer, function-based
mechanism are defined. A complete set of shell functions based on these
features is described in the next chapter, *Note Completion System::,
and users with no interest in adding to that system (or, potentially,
writing their own -- see dictionary entry for `hubris') should skip the
current section. The older system based on the compctl builtin command
is described in *Note Completion Using compctl::.
Completion widgets are defined by the -C option to the zle builtin
command provided by the zsh/zle module (see *Note The zsh/zle
Module::). For example,
zle -C complete expand-or-complete completer
defines a widget named `complete'. The second argument is the name of
any of the builtin widgets that handle completions: complete-word,
expand-or-complete, expand-or-complete-prefix, menu-complete,
menu-expand-or-complete, reverse-menu-complete, list-choices, or
delete-char-or-list. Note that this will still work even if the widget
in question has been re-bound.
When this newly defined widget is bound to a key using the bindkey
builtin command defined in the zsh/zle module (*Note Zsh Line
Editor::), typing that key will call the shell function `completer'.
This function is responsible for generating the possible matches using
the builtins described below. As with other ZLE widgets, the function
is called with its standard input closed.
Once the function returns, the completion code takes over control again
and treats the matches in the same manner as the specified builtin
widget, in this case expand-or-complete.
* Menu:
* Completion Special Parameters::
* Completion Builtin Commands::
* Completion Condition Codes::
* Completion Matching Control::
* Completion Widget Example::
File: zsh.info, Node: Completion Special Parameters, Next: Completion Builtin Commands, Up: Completion Widgets
19.2 Completion Special Parameters
==================================
The parameters ZLE_REMOVE_SUFFIX_CHARS and ZLE_SPACE_SUFFIX_CHARS are
used by the completion mechanism, but are not special. *Note
Parameters Used By The Shell::.
Inside completion widgets, and any functions called from them, some
parameters have special meaning; outside these functions they are not
special to the shell in any way. These parameters are used to pass
information between the completion code and the completion widget. Some
of the builtin commands and the condition codes use or change the
current values of these parameters. Any existing values will be hidden
during execution of completion widgets; except for compstate, the
parameters are reset on each function exit (including nested function
calls from within the completion widget) to the values they had when
the function was entered.
CURRENT
This is the number of the current word, i.e. the word the cursor is
currently on in the words array. Note that this value is only
correct if the ksharrays option is not set.
IPREFIX
Initially this will be set to the empty string. This parameter
functions like PREFIX; it contains a string which precedes the one
in PREFIX and is not considered part of the list of matches.
Typically, a string is transferred from the beginning of PREFIX to
the end of IPREFIX, for example:
IPREFIX=${PREFIX%%\=*}=
PREFIX=${PREFIX#*=}
causes the part of the prefix up to and including the first equal
sign not to be treated as part of a matched string. This can be
done automatically by the compset builtin, see below.
ISUFFIX
As IPREFIX, but for a suffix that should not be considered part of
the matches; note that the ISUFFIX string follows the SUFFIX
string.
PREFIX
Initially this will be set to the part of the current word from the
beginning of the word up to the position of the cursor; it may be
altered to give a common prefix for all matches.
QIPREFIX
This parameter is read-only and contains the quoted string up to
the word being completed. E.g. when completing `"foo', this
parameter contains the double quote. If the -q option of compset
is used (see below), and the original string was `"foo bar' with
the cursor on the `bar', this parameter contains `"foo '.
QISUFFIX
Like QIPREFIX, but containing the suffix.
SUFFIX
Initially this will be set to the part of the current word from the
cursor position to the end; it may be altered to give a common
suffix for all matches. It is most useful when the option
COMPLETE_IN_WORD is set, as otherwise the whole word on the
command line is treated as a prefix.
compstate
This is an associative array with various keys and values that the
completion code uses to exchange information with the completion
widget. The keys are:
all_quotes
The -q option of the compset builtin command (see below)
allows a quoted string to be broken into separate words; if
the cursor is on one of those words, that word will be
completed, possibly invoking `compset -q' recursively. With
this key it is possible to test the types of quoted strings
which are currently broken into parts in this fashion. Its
value contains one character for each quoting level. The
characters are a single quote or a double quote for strings
quoted with these characters, a dollars sign for strings
quoted with $'...' and a backslash for strings not starting
with a quote character. The first character in the value
always corresponds to the innermost quoting level.
context
This will be set by the completion code to the overall context
in which completion is attempted. Possible values are:
array_value
when completing inside the value of an array parameter
assignment; in this case the words array contains the
words inside the parentheses.
brace_parameter
when completing the name of a parameter in a parameter
expansion beginning with ${.
assign_parameter
when completing the name of a parameter in a parameter
assignment.
command
when completing for a normal command (either in command
position or for an argument of the command).
condition
when completing inside a `[[...]]' conditional
expression; in this case the words array contains only
the words inside the conditional expression.
math
when completing in a mathematical environment such as a
`((...))' construct.
parameter
when completing the name of a parameter in a parameter
expansion beginning with $ but not ${.
redirect
when completing after a redirection operator.
subscript
when completing inside a parameter subscript.
value
when completing the value of a parameter assignment.
exact
Controls the behaviour when the REC_EXACT option is set. It
will be set to accept if an exact match would be accepted,
and will be unset otherwise.
If it was set when at least one match equal to the string on
the line was generated, the match is accepted.
exact_string
The string of an exact match if one was found, otherwise
unset.
ignored
The number of words that were ignored because they matched
one of the patterns given with the -F option to the compadd
builtin command.
insert
This controls the manner in which a match is inserted into
the command line. On entry to the widget function, if it is
unset the command line is not to be changed; if set to
unambiguous, any prefix common to all matches is to be
inserted; if set to automenu-unambiguous, the common prefix
is to be inserted and the next invocation of the completion
code may start menu completion (due to the AUTO_MENU option
being set); if set to menu or automenu menu completion will
be started for the matches currently generated (in the latter
case this will happen because the AUTO_MENU is set). The
value may also contain the string `tab' when the completion
code would normally not really do completion, but only insert
the TAB character.
On exit it may be set to any of the values above (where
setting it to the empty string is the same as unsetting it),
or to a number, in which case the match whose number is given
will be inserted into the command line. Negative numbers
count backward from the last match (with `-1' selecting the
last match) and out-of-range values are wrapped around, so
that a value of zero selects the last match and a value one
more than the maximum selects the first. Unless the value of
this key ends in a space, the match is inserted as in a menu
completion, i.e. without automatically appending a space.
Both menu and automenu may also specify the the number of the
match to insert, given after a colon. For example, `menu:2'
says to start menu completion, beginning with the second
match.
Note that a value containing the substring `tab' makes the
matches generated be ignored and only the TAB be inserted.
Finally, it may also be set to all, which makes all matches
generated be inserted into the line.
insert_positions
When the completion system inserts an unambiguous string into
the line, there may be multiple places where characters are
missing or where the character inserted differs from at least
one match. The value of this key contains a colon separated
list of all these positions, as indexes into the command line.
last_prompt
If this is set to a non-empty string for every match added,
the completion code will move the cursor back to the previous
prompt after the list of completions has been displayed.
Initially this is set or unset according to the
ALWAYS_LAST_PROMPT option.
list
This controls whether or how the list of matches will be
displayed. If it is unset or empty they will never be
listed; if its value begins with list, they will always be
listed; if it begins with autolist or ambiguous, they will be
listed when the AUTO_LIST or LIST_AMBIGUOUS options
respectively would normally cause them to be.
If the substring force appears in the value, this makes the
list be shown even if there is only one match. Normally, the
list would be shown only if there are at least two matches.
The value contains the substring packed if the LIST_PACKED
option is set. If this substring is given for all matches
added to a group, this group will show the LIST_PACKED
behavior. The same is done for the LIST_ROWS_FIRST option
with the substring rows.
Finally, if the value contains the string explanations, only
the explanation strings, if any, will be listed and if it
contains messages, only the messages (added with the -x
option of compadd) will be listed. If it contains both
explanations and messages both kinds of explanation strings
will be listed. It will be set appropriately on entry to a
completion widget and may be changed there.
list_lines
This gives the number of lines that are needed to display the
full list of completions. Note that to calculate the total
number of lines to display you need to add the number of
lines needed for the command line to this value, this is
available as the value of the BUFFERLINES special parameter.
list_max
Initially this is set to the value of the LISTMAX parameter.
It may be set to any other value; when the widget exits this
value will be used in the same way as the value of LISTMAX.
nmatches
The number of matches generated and accepted by the
completion code so far.
old_insert
On entry to the widget this will be set to the number of the
match of an old list of completions that is currently
inserted into the command line. If no match has been
inserted, this is unset.
As with old_list, the value of this key will only be used if
it is the string keep. If it was set to this value by the
widget and there was an old match inserted into the command
line, this match will be kept and if the value of the insert
key specifies that another match should be inserted, this
will be inserted after the old one.
old_list
This is set to yes if there is still a valid list of
completions from a previous completion at the time the widget
is invoked. This will usually be the case if and only if the
previous editing operation was a completion widget or one of
the builtin completion functions. If there is a valid list
and it is also currently shown on the screen, the value of
this key is shown.
After the widget has exited the value of this key is only
used if it was set to keep. In this case the completion code
will continue to use this old list. If the widget generated
new matches, they will not be used.
parameter
The name of the parameter when completing in a subscript or
in the value of a parameter assignment.
pattern_insert
Normally this is set to menu, which specifies that menu
completion will be used whenever a set of matches was
generated using pattern matching. If it is set to any other
non-empty string by the user and menu completion is not
selected by other option settings, the code will instead
insert any common prefix for the generated matches as with
normal completion.
pattern_match
Locally controls the behaviour given by the GLOB_COMPLETE
option. Initially it is set to `*' if and only if the option
is set. The completion widget may set it to this value, to
an empty string (which has the same effect as unsetting it),
or to any other non-empty string. If it is non-empty,
unquoted metacharacters on the command line will be treated
as patterns; if it is `*', then additionally a wildcard `*'
is assumed at the cursor position; if it is empty or unset,
metacharacters will be treated literally.
Note that the matcher specifications given to the compadd
builtin command are not used if this is set to a non-empty
string.
quote
When completing inside quotes, this contains the quotation
character (i.e. either a single quote, a double quote, or a
backtick). Otherwise it is unset.
quoting
When completing inside single quotes, this is set to the
string single; inside double quotes, the string double;
inside backticks, the string backtick. Otherwise it is unset.
redirect
The redirection operator when completing in a redirection
position, i.e. one of <, >, etc.
restore
This is set to auto before a function is entered, which
forces the special parameters mentioned above (words,
CURRENT, PREFIX, IPREFIX, SUFFIX, and ISUFFIX) to be restored
to their previous values when the function exits. If a
function unsets it or sets it to any other string, they will
not be restored.
to_end
Specifies the occasions on which the cursor is moved to the
end of a string when a match is inserted. On entry to a
widget function, it may be single if this will happen when a
single unambiguous match was inserted or match if it will
happen any time a match is inserted (for example, by menu
completion; this is likely to be the effect of the
ALWAYS_TO_END option).
On exit, it may be set to single as above. It may also be
set to always, or to the empty string or unset; in those
cases the cursor will be moved to the end of the string
always or never respectively. Any other string is treated as
match.
unambiguous
This key is read-only and will always be set to the common
(unambiguous) prefix the completion code has generated for
all matches added so far.
unambiguous_cursor
This gives the position the cursor would be placed at if the
common prefix in the unambiguous key were inserted, relative
to the value of that key. The cursor would be placed before
the character whose index is given by this key.
unambiguous_positions
This contains all positions where characters in the
unambiguous string are missing or where the character
inserted differs from at least one of the matches. The
positions are given as indexes into the string given by the
value of the unambiguous key.
vared
If completion is called while editing a line using the vared
builtin, the value of this key is set to the name of the
parameter given as an argument to vared. This key is only
set while a vared command is active.
words
This array contains the words present on the command line
currently being edited.
File: zsh.info, Node: Completion Builtin Commands, Next: Completion Condition Codes, Prev: Completion Special Parameters, Up: Completion Widgets
19.3 Completion Builtin Commands
================================
compadd [ -akqQfenUld12C ] [ -F ARRAY ]
[ -P PREFIX ] [ -S SUFFIX ]
[ -p HIDDEN-PREFIX ] [ -s HIDDEN-SUFFIX ]
[ -i IGNORED-PREFIX ] [ -I IGNORED-SUFFIX ]
[ -W FILE-PREFIX ] [ -d ARRAY ]
[ -J NAME ] [ -V NAME ] [ -X EXPLANATION ] [ -x MESSAGE ]
[ -r REMOVE-CHARS ] [ -R REMOVE-FUNC ]
[ -D ARRAY ] [ -O ARRAY ] [ -A ARRAY ]
[ -E NUMBER ]
[ -M MATCH-SPEC ] [ -- ] [ WORDS ... ]
This builtin command can be used to add matches directly and
control all the information the completion code stores with each
possible match. The return status is zero if at least one match
was added and non-zero if no matches were added.
The completion code breaks the string to complete into seven
fields in the order:
<IPRE><APRE><HPRE><WORD><HSUF><ASUF><ISUF>
The first field is an ignored prefix taken from the command line,
the contents of the IPREFIX parameter plus the string given with
the -i option. With the -U option, only the string from the -i
option is used. The field <APRE> is an optional prefix string
given with the -P option. The <HPRE> field is a string that is
considered part of the match but that should not be shown when
listing completions, given with the -p option; for example,
functions that do filename generation might specify a common path
prefix this way. <WORD> is the part of the match that should
appear in the list of completions, i.e. one of the WORDS given at
the end of the compadd command line. The suffixes <HSUF>, <ASUF>
and <ISUF> correspond to the prefixes <HPRE>, <APRE> and <IPRE>
and are given by the options -s, -S and -I, respectively.
The supported flags are:
-P PREFIX
This gives a string to be inserted before the given WORDS.
The string given is not considered as part of the match and
any shell metacharacters in it will not be quoted when the
string is inserted.
-S SUFFIX
Like -P, but gives a string to be inserted after the match.
-p HIDDEN-PREFIX
This gives a string that should be inserted into the command
line before the match but that should not appear in the list
of matches. Unless the -U option is given, this string must
be matched as part of the string on the command line.
-s HIDDEN-SUFFIX
Like `-p', but gives a string to insert after the match.
-i IGNORED-PREFIX
This gives a string to insert into the command line just
before any string given with the `-P' option. Without `-P'
the string is inserted before the string given with `-p' or
directly before the match.
-I IGNORED-SUFFIX
Like -i, but gives an ignored suffix.
-a
With this flag the WORDS are taken as names of arrays and the
possible matches are their values. If only some elements of
the arrays are needed, the WORDS may also contain subscripts,
as in `foo[2,-1]'.
-k
With this flag the WORDS are taken as names of associative
arrays and the possible matches are their keys. As for -a,
the WORDS may also contain subscripts, as in `foo[(R)*bar*]'.
-d ARRAY
This adds per-match display strings. The ARRAY should contain
one element per WORD given. The completion code will then
display the first element instead of the first WORD, and so
on. The ARRAY may be given as the name of an array parameter
or directly as a space-separated list of words in parentheses.
If there are fewer display strings than WORDS, the leftover
WORDS will be displayed unchanged and if there are more
display strings than WORDS, the leftover display strings will
be silently ignored.
-l
This option only has an effect if used together with the -d
option. If it is given, the display strings are listed one
per line, not arrayed in columns.
-o
This option only has an effect if used together with the -d
option. If it is given, the order of the output is
determined by the match strings; otherwise it is determined
by the display strings (i.e. the strings given by the -d
option).
-J NAME
Gives the name of the group of matches the words should be
stored in.
-V NAME
Like -J but naming a unsorted group. These are in a different
name space than groups created with the -J flag.
-1
If given together with the -V option, makes only consecutive
duplicates in the group be removed. If combined with the -J
option, this has no visible effect. Note that groups with and
without this flag are in different name spaces.
-2
If given together with the -J or -V option, makes all
duplicates be kept. Again, groups with and without this flag
are in different name spaces.
-X EXPLANATION
The EXPLANATION string will be printed with the list of
matches, above the group currently selected.
-x MESSAGE
Like -X, but the MESSAGE will be printed even if there are no
matches in the group.
-q
The suffix given with -S will be automatically removed if the
next character typed is a blank or does not insert anything,
or if the suffix consists of only one character and the next
character typed is the same character.
-r REMOVE-CHARS
This is a more versatile form of the -q option. The suffix
given with -S or the slash automatically added after
completing directories will be automatically removed if the
next character typed inserts one of the characters given in
the REMOVE-CHARS. This string is parsed as a characters
class and understands the backslash sequences used by the
print command. For example, `-r "a-z\t"' removes the suffix
if the next character typed inserts a lower case character or
a TAB, and `-r "^0-9"' removes the suffix if the next
character typed inserts anything but a digit. One extra
backslash sequence is understood in this string: `\-' stands
for all characters that insert nothing. Thus `-S "=" -q' is
the same as `-S "=" -r "= \t\n\-"'.
This option may also be used without the -S option; then any
automatically added space will be removed when one of the
characters in the list is typed.
-R REMOVE-FUNC
This is another form of the -r option. When a suffix has been
inserted and the completion accepted, the function
REMOVE-FUNC will be called after the next character typed.
It is passed the length of the suffix as an argument and can
use the special parameters available in ordinary
(non-completion) zle widgets (see *Note Zsh Line Editor::) to
analyse and modify the command line.
-f
If this flag is given, all of the matches built from WORDS are
marked as being the names of files. They are not required to
be actual filenames, but if they are, and the option
LIST_TYPES is set, the characters describing the types of the
files in the completion lists will be shown. This also forces
a slash to be added when the name of a directory is completed.
-e
This flag can be used to tell the completion code that the
matches added are parameter names for a parameter expansion.
This will make the AUTO_PARAM_SLASH and AUTO_PARAM_KEYS
options be used for the matches.
-W FILE-PREFIX
This string is a pathname that will be prepended to each of
the matches formed by the given WORDS together with any
prefix specified by the -p option to form a complete filename
for testing. Hence it is only useful if combined with the -f
flag, as the tests will not otherwise be performed.
-F ARRAY
Specifies an array containing patterns. Words matching one of
these patterns are ignored, i.e. not considered to be
possible matches.
The ARRAY may be the name of an array parameter or a list of
literal patterns enclosed in parentheses and quoted, as in
`-F "(*?.o *?.h)"'. If the name of an array is given, the
elements of the array are taken as the patterns.
-Q
This flag instructs the completion code not to quote any
metacharacters in the words when inserting them into the
command line.
-M MATCH-SPEC
This gives local match specifications as described below in
*Note Completion Matching Control::. This option may be given
more than once. In this case all MATCH-SPECs given are
concatenated with spaces between them to form the
specification string to use. Note that they will only be
used if the -U option is not given.
-n
Specifies that the words added are to be used as possible
matches, but are not to appear in the com