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 con‐
     vert  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.

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 op‐
            tion 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 hexadec‐
            imal  and  followed by an ASCII (or EBCDIC) representation. The com‐
            mand 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 grouping of 4 bytes
            may be changed using -g.  This option only applies to the hex  dump,
            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. 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 truncat‐
            ing it. Use the combination -r -p to read  plain  hexadecimal  dumps
            without line number information and without a particular column lay‐
            out. Additional whitespace and line breaks are allowed 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 differenti‐
            ate printable and non-printable characters.  when is never,  always,
            or auto (default: auto).  When the $NO_COLOR environment 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 (mean‐
            ingless when not reading from stdin).  -  indicates  that  the  seek
            should be that many characters from the end of the input (or if com‐
            bined  with  +: before the current stdin file position).  Without -s
            option, xxd starts at the current file position.

     -t     When outputting in C include file style using -i include the  termi‐
            nating zero.

     -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 information.
     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 in‐
     put 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 March 2026

     Print 120 bytes as a continuous hex dump with 20 octets per line.
     % xxd -l 120 -ps -c 20 xxd.1
     2e544820585844203120224d6172203230323622
     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: 6172 2032 3032 3622 2022 4d61  ar 2026" "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  after
     '-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 mnv(1) to hex  dump  a  region
     marked between ‘a' and ‘z'.
     :'a,'z!xxd

     Use xxd as a filter within an editor such as mnv(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 mnv(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

     Output in C style include output with terminating zero
     % echo -n "0123456789" > digits
     % xxd -i -t digits
     unsigned char digits[] = {
       0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x00
     };
     unsigned int digits_len = 10;

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                 Mar 2026                              XXD(1)
