XXD(1) - phpMan

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XXD(1)                                                                  XXD(1)



NAME
       xxd - make a hexdump or do the reverse.

SYNOPSIS
       xxd -h[elp]
       xxd [options] [infile [outfile]]
       xxd -r[evert] [options] [infile [outfile]]

DESCRIPTION
       xxd  creates  a  hex dump of a given file or standard input.  It can also convert a
       hex dump back to its original binary form.  Like  uuencode(1)  and  uudecode(1)  it
       allows  the  transmission of binary data in a 'mail-safe' ASCII representation, but
       has the advantage of decoding to standard output.  Moreover, it can be used to per-
       form binary file patching.

OPTIONS
       If  no  infile  is  given, standard input is read.  If infile is specified as a `-'
       character, then input is taken from standard input.  If no outfile is given  (or  a
       `-' character is in its place), results are sent to standard output.

       Note  that  a  "lazy"  parser  is used which does not check for more than the first
       option letter, unless the option is followed by a parameter.  Spaces between a sin-
       gle  option  letter  and  its parameter are optional.  Parameters to options can be
       specified in decimal, hexadecimal or octal notation.  Thus -c8, -c 8,  -c  010  and
       -cols 8 are all equivalent.


       -a | -autoskip
              toggle autoskip: A single '*' replaces nul-lines.  Default off.

       -b | -bits
              Switch  to  bits  (binary  digits)  dump,  rather than hexdump.  This option
              writes octets as eight digits "1"s and "0"s instead of a normal  hexadecimal
              dump.  Each line is preceded by a line number in hexadecimal and followed by
              an ascii (or ebcdic) representation. The command line switches -r, -p, -i do
              not work with this mode.

       -c cols | -cols cols
              format <cols> octets per line. Default 16 (-i: 12, -ps: 30, -b: 6). Max 256.

       -E | -EBCDIC
              Change the character encoding in the righthand column from ASCII to  EBCDIC.
              This  does not change the hexadecimal representation. The option is meaning-
              less in combinations with -r, -p or -i.

       -g bytes | -groupsize bytes
              separate the output of every <bytes> bytes (two hex characters or eight bit-
              digits  each)  by a whitespace.  Specify -g 0 to suppress grouping.  <Bytes>
              defaults to 2 in normal mode and 1 in bits mode.  Grouping does not apply to
              postscript or include style.

       -h | -help
              print  a  summary  of  available  commands and exit.  No hex dumping is per-
              formed.

       -i | -include
              output in C include file style. A complete static array definition is  writ-
              ten (named after the input file), unless xxd reads from stdin.

       -l len | -len len
              stop after writing <len> octets.

       -p | -ps | -postscript | -plain
              output  in  postscript continuous hexdump style. Also known as plain hexdump
              style.

       -r | -revert
              reverse operation: convert (or patch) hexdump into binary.  If  not  writing
              to  stdout,  xxd  writes into its output file without truncating it. Use the
              combination -r -p to read plain hexadecimal dumps without line number infor-
              mation  and  without  a  particular column layout. Additional Whitespace and
              line-breaks are allowed anywhere.

       -seek offset
              When used after -r: revert with <offset> added to file  positions  found  in
              hexdump.

       -s [+][-]seek
              start  at  <seek>  bytes abs. (or rel.) infile offset.  + indicates that the
              seek is relative to the current stdin file position  (meaningless  when  not
              reading  from stdin).  - indicates that the seek should be that many charac-
              ters from the end of the input (or if combined with +:  before  the  current
              stdin  file  position).   Without  -s option, xxd starts at the current file
              position.

       -u     use upper case hex letters. Default is lower case.

       -v | -version
              show version string.

CAVEATS
       xxd -r has some builtin magic while evaluating line  number  information.   If  the
       output file is seekable, then the linenumbers at the start of each hexdump line may
       be out of order, lines may be missing, or overlapping.  In  these  cases  xxd  will
       lseek(2)  to  the  next position. If the output file is not seekable, only gaps are
       allowed, which will be filled by null-bytes.

       xxd -r never generates parse errors. Garbage is silently skipped.

       When editing hexdumps, please note that xxd -r skips everything on the  input  line
       after  reading enough columns of hexadecimal data (see option -c). This also means,
       that changes to the printable ascii (or ebcdic) columns are always ignored. Revert-
       ing  a  plain  (or  postscript) style hexdump with xxd -r -p does not depend on the
       correct number of columns. Here anything that looks like a pair  of  hex-digits  is
       interpreted.

       Note the difference between
       % xxd -i file
       and
       % xxd -i < file

       xxd  -s  +seek  may  be different from xxd -s seek, as lseek(2) is used to "rewind"
       input.  A '+' makes a difference if the input source is stdin, and if stdin's  file
       position  is  not at the start of the file by the time xxd is started and given its
       input.  The following examples may help to clarify (or further confuse!)...

       Rewind stdin before reading; needed because the 'cat' has already read to  the  end
       of stdin.
       % sh -c "cat > plain_copy; xxd -s 0 > hex_copy" < file

       Hexdump from file position 0x480 (=1024+128) onwards.  The '+' sign means "relative
       to the current position", thus the '128' adds to the 1k where dd left off.
       % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +128 > hex_snippet" < file

       Hexdump from file position 0x100 ( = 1024-768) on.
       % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +-768 > hex_snippet" < file

       However, this is a rare situation and the use of '+' is rarely needed.  The  author
       prefers  to  monitor  the  effect of xxd with strace(1) or truss(1), whenever -s is
       used.

EXAMPLES
       Print everything but the first three lines (hex 0x30 bytes) of file.
       % xxd -s 0x30 file

       Print 3 lines (hex 0x30 bytes) from the end of file.
       % xxd -s -0x30 file

       Print 120 bytes as continuous hexdump with 20 octets per line.
       % xxd -l 120 -ps -c 20 xxd.1
       2e54482058584420312022417567757374203139
       39362220224d616e75616c207061676520666f72
       20787864220a2e5c220a2e5c222032317374204d
       617920313939360a2e5c22204d616e2070616765
       20617574686f723a0a2e5c2220202020546f6e79
       204e7567656e74203c746f6e79407363746e7567

       Hexdump the first 120 bytes of this man page with 12 octets per line.
       % xxd -l 120 -c 12 xxd.1
       0000000: 2e54 4820 5858 4420 3120 2241  .TH XXD 1 "A
       000000c: 7567 7573 7420 3139 3936 2220  ugust 1996"
       0000018: 224d 616e 7561 6c20 7061 6765  "Manual page
       0000024: 2066 6f72 2078 7864 220a 2e5c   for xxd"..\
       0000030: 220a 2e5c 2220 3231 7374 204d  "..\" 21st M
       000003c: 6179 2031 3939 360a 2e5c 2220  ay 1996..\"
       0000048: 4d61 6e20 7061 6765 2061 7574  Man page aut
       0000054: 686f 723a 0a2e 5c22 2020 2020  hor:..\"
       0000060: 546f 6e79 204e 7567 656e 7420  Tony Nugent
       000006c: 3c74 6f6e 7940 7363 746e 7567  <tony@sctnug

       Display just the date from the file xxd.1
       % xxd -s 0x36 -l 13 -c 13 xxd.1
       0000036: 3231 7374 204d 6179 2031 3939 36  21st May 1996

       Copy input_file to output_file and prepend 100 bytes of value 0x00.
       % xxd input_file | xxd -r -s 100 > output_file

       Patch the date in the file xxd.1
       % echo "0000037: 3574 68" | xxd -r - xxd.1
       % xxd -s 0x36 -l 13 -c 13 xxd.1
       0000036: 3235 7468 204d 6179 2031 3939 36  25th May 1996

       Create a 65537 byte file with all bytes 0x00, except for the last one which is  'A'
       (hex 0x41).
       % echo "010000: 41" | xxd -r > file

       Hexdump this file with autoskip.
       % xxd -a -c 12 file
       0000000: 0000 0000 0000 0000 0000 0000  ............
       *
       000fffc: 0000 0000 40                   ....A

       Create  a  1 byte file containing a single 'A' character.  The number after '-r -s'
       adds to the linenumbers found in the file; in effect, the leading  bytes  are  sup-
       pressed.
       % echo "010000: 41" | xxd -r -s -0x10000 > file

       Use  xxd  as  a  filter  within an editor such as vim(1) to hexdump a region marked
       between 'a' and 'z'.
       :'a,'z!xxd

       Use xxd as a filter within an editor such as vim(1) to  recover  a  binary  hexdump
       marked between 'a' and 'z'.
       :'a,'z!xxd -r

       Use  xxd  as a filter within an editor such as vim(1) to recover one line of a hex-
       dump.  Move the cursor over the line and type:
       !!xxd -r

       Read single characters from a serial line
       % xxd -c1 < /dev/term/b &
       % stty < /dev/term/b -echo -opost -isig -icanon min 1
       % echo -n foo > /dev/term/b


RETURN VALUES
       The following error values are returned:

       0      no errors encountered.

       -1     operation not supported ( xxd -r -i still impossible).

       1      error while parsing options.

       2      problems with input file.

       3      problems with output file.

       4,5    desired seek position is unreachable.

SEE ALSO
       uuencode(1), uudecode(1), patch(1)

WARNINGS
       The tools weirdness matches its creators brain.  Use entirely  at  your  own  risk.
       Copy files. Trace it. Become a wizard.

VERSION
       This manual page documents xxd version 1.7

AUTHOR
       (c) 1990-1997 by Juergen Weigert
       <jnweiger AT informatik.de>

       Distribute freely and credit me,
       make money and share with me,
       lose money and don't ask me.

       Manual page started by Tony Nugent
       <tony AT sctnugen.au> <T.Nugent AT sct.au>
       Small changes by Bram Moolenaar.  Edited by Juergen Weigert.




Manual page for xxd               August 1996                           XXD(1)

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