ZSHPARAM(1) - phpMan

Command: man perldoc info search(apropos)  


ZSHPARAM(1)                                                        ZSHPARAM(1)



NAME
       zshparam - zsh parameters

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 the section 'Array Parameters' for additional  forms  of  assign-
       ment.

       To  refer  to  the value of a parameter, write '$name' or '${name}'.  See Parameter
       Expansion in zshexpn(1) 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.

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 param-
       eter  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=()


   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 equiv-
       alent; see the description of the option in zshoptions(1).

       The  same subscripting syntax is used for associative arrays, except that no arith-
       metic 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 Parameter Expansion Flags in zsh-
       expn(1) 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  ele-
       ment  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  sub-
       scripts  specify  a substring to be extracted.  For example, if FOO is set to 'foo-
       bar', then 'echo $FOO[2,5]' prints 'ooba'.


   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 cre-
       ated 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 assign-
       ments 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]"


   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  whites-
              pace.  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 argu-
              ment 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  new-
              lines.  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 sub-
              stitute 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 corre-
                     sponding 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 pat-
                     tern matching).  The flag 'e' can be added to inhibit pattern  match-
                     ing.  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 substi-
              tutes  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  arbi-
              trary; see above.

       e      This  flag  causes  any pattern matching that would be performed on the sub-
              script 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 (zshexpn(1)) for additional ways  to  manipulate  the
       results of array subscripting.


   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 (see zshmisc(1)).  However, unlike double quotes which normally cannot nest,
       subscript  expressions may appear inside double-quoted strings or inside other sub-
       script 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 brack-
       ets!

       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  sub-
       script 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 dou-
       ble-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 differ-
       ent 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.   Parame-
       ters 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,  parenthe-
       ses,  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}' (see zshexpn(1)) 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 sub-
       script is a plain string in that case.)

       One final note, not directly related to subscripting: the numeric  names  of  posi-
       tional parameters (described below) 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 exam-
       ple, '${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]'.


POSITIONAL PARAMETERS
       The positional parameters provide access to the command-line arguments of  a  shell
       function, shell script, or the shell itself; see the section 'Invocation', and also
       the section 'Functions'.  The parameter n, where n is a number, is  the  nth  posi-
       tional parameter.  The parameters *, @ and argv are arrays containing all the posi-
       tional 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  neces-
       sary to accommodate the new values.


LOCAL PARAMETERS
       Shell  function  executions  delimit  scopes for shell parameters.  (Parameters are
       dynamically scoped.)  The typeset builtin, and its alternative forms declare, inte-
       ger,  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.)  How-
       ever, assigning to a non-existent parameter, or  declaring  a  new  parameter  with
       export, causes it to be created in the outermost 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.


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 exe-
              cuting 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 func-
              tion 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 com-
              mand.

       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 privi-
              leges, you may change the effective group ID of the shell process by assign-
              ing to this parameter.  Also (assuming sufficient privileges), you may start
              a single command with a different effective group  ID  by  '(EGID=gid;  com-
              mand)'

       EUID <S>
              The  effective  user ID of the shell process.  If you have sufficient privi-
              leges, you may change the effective user ID of the shell process by  assign-
              ing 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 errno(3)) as set by the most recently failed system
              call.  This value is system dependent and is  intended  for  debugging  pur-
              poses.  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 param-
              eter.  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 zshbuiltins(1) 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 Complex Commands in zshmisc(1)

       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  (assum-
              ing 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_eval_context <S> <Z> (ZSH_EVAL_CONTEXT <S>)
              An array (colon-separated list) indicating the context of shell code that is
              being  run.  Each time a piece of shell code that is stored within the shell
              is executed a string is temporarily appended to the array  to  indicate  the
              type of operation that is being performed.  Read in order the array gives an
              indication of the stack of operations being performed with the most  immedi-
              ate context last.

              Note  that  the variable does not give information on syntactic context such
              as pipelines or subshells.  Use $ZSH_SUBSHELL to detect subshells.

              The context is one of the following:
              cmdarg Code specified by the -c option to the command line that invoked  the
                     shell.

              cmdsubst
                     Command substitution using the '...' or $(...) construct.

              equalsubst
                     File substitution using the =(...) construct.

              eval   Code executed by the eval builtin.

              evalautofunc
                     Code  executed  with the KSH_AUTOLOAD mechanism in order to define an
                     autoloaded function.

              fc     Code from the shell history executed by  the  -e  option  to  the  fc
                     builtin.

              file   Lines  of  code  being  read directly from a file, for example by the
                     source builtin.

              filecode
                     Lines of code being read from a .zwc file instead  of  directly  from
                     the source file.

              globqual
                     Code executed by the e or + glob qualifier.

              globsort
                     Code executed to order files by the o glob qualifier.

              insubst
                     File substitution using the <(...) construct.

              loadautofunc
                     Code read directly from a file to define an autoloaded function.

              outsubst
                     File substitution using the >(...) construct.

              sched  Code executed by the sched builtin.

              shfunc A shell function.

              stty   Code  passed to stty by the STTY environment variable.  Normally this
                     is passed directly to the system's stty command,  so  this  value  is
                     unlikely to be seen in practice.

              style  Code executed as part of a style retrieved by the zstyle builtin from
                     the zsh/zutil module.

              toplevel
                     The highest execution level of a script or interactive shell.

              trap   Code executed as a trap defined by the trap builtin.   Traps  defined
                     as functions have the context shfunc.  As traps are asynchronous they
                     may have a different hierarchy from other code.

              zpty   Code executed by the zpty builtin from the zsh/zpty module.

              zregexparse-guard
                     Code executed  as  a  guard  by  the  zregexparse  command  from  the
                     zsh/zutil module.

              zregexparse-action
                     Code  executed  as  an  action  by  the  zregexparse command from the
                     zsh/zutil module.

       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 the section 'The zsh/sched Module' in zshmodules(1).

       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.

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 recreat-
       ing 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  parame-
              ter 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  begin-
              ning  with  '_') will never be offered as spelling corrections.  The pattern
              does not apply to the correction of file  names,  as  applied  by  the  COR-
              RECT_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, by default there is no  limit.   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  dupli-
              cated 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.

       KEYBOARD_HACK
              This variable defines a character to be removed from the end of the  command
              line before interpreting it (interactive shells only). It is intended to fix
              the problem with keys placed annoyingly close to  return  and  replaces  the
              SUNKEYBOARDHACK  option which did this for backquotes only.  Should the cho-
              sen character be one of singlequote, doublequote or  backquote,  there  must
              also  be  an  odd  number of them on the command line for the last one to be
              removed.

       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 specifi-
              cally 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 infor-
              mation within ranges in glob brackets and for sorting.

       LC_CTYPE <S>
              This variable determines the locale category for  character  handling  func-
              tions.   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 sin-
              gle-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  arith-
              metic  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 param-
              eter 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, 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 EXPANSION OF PROMPT
              SEQUENCES in zshmisc(1).  The default is '%m%# '.

       PS2 <S>
              The secondary prompt, printed when the shell needs more information to  com-
              plete  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 redirec-
              tion 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 pri-
              mary prompt is being displayed on the left.  This does not work if the  SIN-
              GLE_LINE_ZLE 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 sec-
              ondary prompt is being displayed on the left.  This does  not  work  if  the
              SINGLE_LINE_ZLE 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 spec-
              ified 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.

       TERMINFO <S>
              A reference to a compiled description of the terminal,  used  by  the  'ter-
              minfo' library when the system has it; see terminfo(5).  If set, this causes
              the shell to reinitialise the terminal, making the  workaround  'TERM=$TERM'
              unnecessary.

       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  min-
              utes 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  avail-
                     able 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 sepa-
                     rators 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 the zsh/zle module entry in zshmod-
              ules(1), 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_LINE_ABORTED
              This parameter is set by the line editor when an error occurs.  It  contains
              the  line  that  was  being edited at the point of the error.  'print -zr --
              $ZLE_LINE_ABORTED' can be used to recover the line.  Only  the  most  recent
              line of this kind is remembered.

       ZLE_REMOVE_SUFFIX_CHARS
       ZLE_SPACE_SUFFIX_CHARS
              These parameters are used by the line editor.  In certain circumstances suf-
              fixes (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 suf-
              fix 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 zshcompsys(1).



zsh 4.3.14                     December 6, 2011                    ZSHPARAM(1)

Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2017-12-13 03:32 @127.0.0.1 CrawledBy CCBot/2.0 (http://commoncrawl.org/faq/)
Valid XHTML 1.0!Valid CSS!