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XXD(1)			    General Commands Manual			XXD(1)

NAME
       xxd - make a hex	dump 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	 stan-
       dard output.  Moreover, it can be used to perform 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 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 hex dump.  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 switch -p does not work with this mode.
	      Can be combined with -i.

       -c cols | -cols cols
	      Format <cols> octets per line. Default 16	(-i: 12, -ps: 30,  -b:
	      6).  Max	256.   No  maximum for -ps. With -ps, 0	results	in one
	      long line	of output.

       -C | -capitalize
	      Capitalize variable names	in C include file  style,  when	 using
	      -i.

       -d     show offset in decimal instead of	hex.

       -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	 hex  dump.   This  option treats byte
	      groups as	words in little-endian byte order.  The	default	group-
	      ing of 4 bytes may be changed using -g.  This  option  only  ap-
	      plies to the hex dump, leaving the ASCII (or EBCDIC) representa-
	      tion  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 sup-
	      press grouping.  <Bytes> defaults	to 2 in	normal mode, 4 in lit-
	      tle-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 defini-
	      tion is written (named after the input file), unless  xxd	 reads
	      from stdin. Can be combined with -b.

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

       -n name	|  -name name
	      Override	the variable name output when -i is used. The array is
	      named name and the length	is named name_len.

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

       -p | -ps	| -postscript |	-plain
	      Output in	PostScript continuous hex dump style.  Also  known  as
	      plain hex	dump style.

       -r | -revert
	      Reverse  operation: convert (or patch) hex dump 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 al-
	      lowed  anywhere.	Use  the combination -r	-b to read a bits dump
	      instead of a hex dump.

       -R when
	      In the output the	hex-value and the value	are both colored  with
	      the  same	 color	depending  on the hex-value. Mostly helping to
	      differentiate printable and non-printable	characters.   when  is
	      never,  always, or auto (default:	auto).	When the $NO_COLOR en-
	      vironment	variable is set, colorization will be disabled.

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

       -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.

CAVEATS
       xxd -r has some built-in	magic while evaluating	line  number  informa-
       tion.   If  the	output	file is	seekable, then the line	numbers	at the
       start of	each hex dump 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 hex	dumps, 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 hex
       dump 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

       Hex  dump  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

       Hex dump	from file position 0x100 (=1024-768) onwards.
       % 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

       Note:  The  results of the examples below are relevant to the xxd.1 man
       page as of May 2024

       Print 120 bytes as a continuous hex dump	with 20	octets per line.
       % xxd -l	120 -ps	-c 20 xxd.1
       2e544820585844203120224d6179203230323422
       20224d616e75616c207061676520666f72207878
       64220a2e5c220a2e5c222032317374204d617920
       313939360a2e5c22204d616e2070616765206175
       74686f723a0a2e5c2220202020546f6e79204e75
       67656e74203c746f6e79407363746e7567656e2e

       Hex dump	the first 120 bytes of this man	page with 12 octets per	line.
       % xxd -l	120 -c 12 xxd.1
       00000000: 2e54 4820 5858	4420 3120 224d	.TH XXD	1 "M
       0000000c: 6179 2032 3032	3422 2022 4d61	ay 2024" "Ma
       00000018: 6e75 616c 2070	6167 6520 666f	nual page fo
       00000024: 7220 7878 6422	0a2e 5c22 0a2e	r xxd"..\"..
       00000030: 5c22 2032 3173	7420 4d61 7920	\" 21st	May
       0000003c: 3139 3936 0a2e	5c22 204d 616e	1996..\" Man
       00000048: 2070 6167 6520	6175 7468 6f72	 page author
       00000054: 3a0a 2e5c 2220	2020 2054 6f6e	:..\"	 Ton
       00000060: 7920 4e75 6765	6e74 203c 746f	y Nugent <to
       0000006c: 6e79 4073 6374	6e75 6765 6e2e	ny@sctnugen.

       Display just the	date from the file xxd.1
       % xxd -s	0x33 -l	13 -c 13 xxd.1
       00000033: 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 "0000034:	3574 68" | xxd -r - xxd.1
       % xxd -s	0x33 -l	13 -c 13 xxd.1
       00000033: 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

       Hex dump	this file with autoskip.
       % xxd -a	-c 12 file
       00000000: 0000 0000 0000	0000 0000 0000	............
       *
       0000fffc: 0000 0000 41			....A

       Create a	1 byte file containing a single	'A' character.	The number af-
       ter  '-r	-s' adds to the	line numbers 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 hex dump	a  re-
       gion marked between `a' and `z'.
       :'a,'z!xxd

       Use xxd as a filter within an editor such as vim(1) to recover a	binary
       hex dump	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 tool's weirdness matches its	creator's brain.  Use entirely at your
       own risk. Copy files. Trace it. Become a	wizard.

VERSION
       This manual page	documents xxd version 1.7 from 2024-05.

AUTHOR
       (c) 1990-1997 by	Juergen	Weigert
       <jnweiger@informatik.uni-erlangen.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@sctnugen.ppp.gu.edu.au> <T.Nugent@sct.gu.edu.au>
       Small changes by	Bram Moolenaar.	 Edited	by Juergen Weigert.

Manual page for	xxd		   May 2024				XXD(1)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=xxd&sektion=1&manpath=FreeBSD+14.3-RELEASE+and+Ports>

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