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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	stan
       dard 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) representa
	      tion. The command line switches -r, -p, -i do not work with this

       -c cols | -cols cols
	      format   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.

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

       -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 defini
	      tion is written (named after the input file), unless  xxd  reads
	      from stdin.

       -l len | -len len
	      stop after writing  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 hexadeci
	      mal dumps without line number information and without a particu
	      lar column layout. Additional  Whitespace  and  line-breaks  are
	      allowed anywhere.

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

       -s [+][-]seek
	      start at  bytes abs. (or rel.) infile offset.   +  fRindi
	      cates  that the seek is relative to the current stdin file posi
	      tion (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

       -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  over
       lapping.  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	inter

       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	stdins	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.

       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 40 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   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 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 dont ask me.

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

Manual page for xxd		  August 1996				XXD(1)

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