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       xxd - make a hexdump or do the reverse.


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


       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 perform binary file patching.


       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 single 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

       -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  meaningless  in
              combinations with -r, -p or -i.

       -e     Switch  to  little-endian  hexdump.   This  option  treats  byte groups as words in
              little-endian byte order.  The default grouping of 4 bytes may be changed using -g.
              This  option  only applies to hexdump, leaving the ASCII (or EBCDIC) representation
              unchanged.  The command line switches -r, -p, -i do not work with this mode.

       -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, 4 in little-endian 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 performed.

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

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

       -o offset
              add <offset> to the displayed file position.

       -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 information and without a
              particular  column  layout.  Additional  Whitespace  and  line-breaks  are  allowed

       -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 characters 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.


       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.  Reverting  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
       % 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
       % 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.


       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

       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
       % 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 suppressed.
       % 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'.

       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  hexdump.
       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


       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.


       uuencode(1), uudecode(1), patch(1)


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


       This manual page documents xxd version 1.7


       (c) 1990-1997 by Juergen Weigert

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

       Manual page started by Tony Nugent
       <> <>
       Small changes by Bram Moolenaar.  Edited by Juergen Weigert.