hexdump(1) — Linux manual page


HEXDUMP(1)                    User Commands                   HEXDUMP(1)

NAME         top

       hexdump - display file contents in hexadecimal, decimal, octal,
       or ascii

       hexdump options file ...

       hd options file ...

DESCRIPTION         top

       The hexdump utility is a filter which displays the specified
       files, or standard input if no files are specified, in a
       user-specified format.

OPTIONS         top

       Below, the length and offset arguments may be followed by the
       multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on
       for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g.,
       "K" has the same meaning as "KiB"), or the suffixes KB (=1000),
       MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.

       -b, --one-byte-octal
           One-byte octal display. Display the input offset in
           hexadecimal, followed by sixteen space-separated,
           three-column, zero-filled bytes of input data, in octal, per

       -X, --one-byte-hex
           One-byte hexadecimal display. Display the input offset in
           hexadecimal, followed by sixteen space-separated, two-column,
           zero-filled bytes of input data, in hexadecimal, per line.

       -c, --one-byte-char
           One-byte character display. Display the input offset in
           hexadecimal, followed by sixteen space-separated,
           three-column, space-filled characters of input data per line.

       -C, --canonical
           Canonical hex+ASCII display. Display the input offset in
           hexadecimal, followed by sixteen space-separated, two-column,
           hexadecimal bytes, followed by the same sixteen bytes in %_p
           format enclosed in | characters. Invoking the program as hd
           implies this option.

       -d, --two-bytes-decimal
           Two-byte decimal display. Display the input offset in
           hexadecimal, followed by eight space-separated, five-column,
           zero-filled, two-byte units of input data, in unsigned
           decimal, per line.

       -e, --format format_string
           Specify a format string to be used for displaying data.

       -f, --format-file file
           Specify a file that contains one or more newline-separated
           format strings. Empty lines and lines whose first non-blank
           character is a hash mark (#) are ignored.

       -L, --color[=when]
           Accept color units for the output. The optional argument when
           can be auto, never or always. If the when argument is
           omitted, it defaults to auto. The colors can be disabled; for
           the current built-in default see the --help output. See also
           the Colors subsection and the COLORS section below.

       -n, --length length
           Interpret only length bytes of input.

       -o, --two-bytes-octal
           Two-byte octal display. Display the input offset in
           hexadecimal, followed by eight space-separated, six-column,
           zero-filled, two-byte quantities of input data, in octal, per

       -s, --skip offset
           Skip offset bytes from the beginning of the input.

       -v, --no-squeezing
           The -v option causes hexdump to display all input data.
           Without the -v option, any number of groups of output lines
           which would be identical to the immediately preceding group
           of output lines (except for the input offsets), are replaced
           with a line comprised of a single asterisk.

       -x, --two-bytes-hex
           Two-byte hexadecimal display. Display the input offset in
           hexadecimal, followed by eight space-separated, four-column,
           zero-filled, two-byte quantities of input data, in
           hexadecimal, per line.

       -h, --help
           Display help text and exit.

       -V, --version
           Print version and exit.

       For each input file, hexdump sequentially copies the input to
       standard output, transforming the data according to the format
       strings specified by the -e and -f options, in the order that
       they were specified.

FORMATS         top

       A format string contains any number of format units, separated by
       whitespace. A format unit contains up to three items: an
       iteration count, a byte count, and a format.

       The iteration count is an optional positive integer, which
       defaults to one. Each format is applied iteration count times.

       The byte count is an optional positive integer. If specified it
       defines the number of bytes to be interpreted by each iteration
       of the format.

       If an iteration count and/or a byte count is specified, a single
       slash must be placed after the iteration count and/or before the
       byte count to disambiguate them. Any whitespace before or after
       the slash is ignored.

       The format is required and must be surrounded by double quote ("
       ") marks. It is interpreted as a fprintf-style format string (see
       fprintf(3)), with the following exceptions:

           An asterisk (*) may not be used as a field width or

           A byte count or field precision is required for each s
           conversion character (unlike the fprintf(3) default which
           prints the entire string if the precision is unspecified).

           The conversion characters h, l, n, p, and q are not

           The single character escape sequences described in the C
           standard are supported:
          │                   │    │
          │ NULL              │ \0 │
          │                   │    │
          │ <alert character> │ \a │
          │                   │    │
          │ <backspace>       │ \b │
          │                   │    │
          │ <form-feed>       │ \f │
          │                   │    │
          │ <newline>         │ \n │
          │                   │    │
          │ <carriage return> │ \r │
          │                   │    │
          │ <tab>             │ \t │
          │                   │    │
          │ <vertical tab>    │ \v │

   Conversion strings
       The hexdump utility also supports the following
       additional conversion strings.

           Display the input offset, cumulative across input
           files, of the next byte to be displayed. The appended
           characters d, o, and x specify the display base as
           decimal, octal or hexadecimal respectively.

           Almost identical to the _a conversion string except
           that it is only performed once, when all of the input
           data has been processed.

           Output characters in the default character set.
           Non-printing characters are displayed in
           three-character, zero-padded octal, except for those
           representable by standard escape notation (see
           above), which are displayed as two-character strings.

           Output characters in the default character set.
           Non-printing characters are displayed as a single

           Output US ASCII characters, with the exception that
           control characters are displayed using the following,
           lower-case, names. Characters greater than 0xff,
           hexadecimal, are displayed as hexadecimal strings.
          │         │         │         │         │         │         │
          │ 000 nul │ 001 soh │ 002 stx │ 003 etx │ 004 eot │ 005 enq │
          │         │         │         │         │         │         │
          │ 006 ack │ 007 bel │ 008 bs  │ 009 ht  │ 00A lf  │ 00B vt  │
          │         │         │         │         │         │         │
          │ 00C ff  │ 00D cr  │ 00E so  │ 00F si  │ 010 dle │ 011 dc1 │
          │         │         │         │         │         │         │
          │ 012 dc2 │ 013 dc3 │ 014 dc4 │ 015 nak │ 016 syn │ 017 etb │
          │         │         │         │         │         │         │
          │ 018 can │ 019 em  │ 01A sub │ 01B esc │ 01C fs  │ 01D gs  │
          │         │         │         │         │         │         │
          │ 01E rs  │ 01F us  │ 0FF del │         │         │         │

       When put at the end of a format specifier,
       hexdump highlights the respective string with the
       color specified. Conditions, if present, are
       evaluated prior to highlighting.


       The full syntax of a color unit is as follows:


           Negate the condition. Please note that it
           only makes sense to negate a unit if both a
           value/string and an offset are specified. In
           that case the respective output string will
           be highlighted if and only if the
           value/string does not match the one at the

           One of the 8 basic shell colors.

           A value to be matched specified in
           hexadecimal, or octal base, or as a string.
           Please note that the usual C escape sequences
           are not interpreted by hexdump inside the

           An offset or an offset range at which to
           check for a match. Please note that lone
           OFFSET_START uses the same value as END

       The default and supported byte counts for the
       conversion characters are as follows:

       %_c, %_p, %_u, %c
           One byte counts only.

       %d, %i, %o, %u, %X, %x
           Four byte default, one, two and four byte
           counts supported.

       %E, %e, %f, %G, %g
           Eight byte default, four byte counts

       The amount of data interpreted by each format
       string is the sum of the data required by each
       format unit, which is the iteration count times
       the byte count, or the iteration count times the
       number of bytes required by the format if the
       byte count is not specified.

       The input is manipulated in blocks, where a block
       is defined as the largest amount of data
       specified by any format string. Format strings
       interpreting less than an input block’s worth of
       data, whose last format unit both interprets some
       number of bytes and does not have a specified
       iteration count, have the iteration count
       incremented until the entire input block has been
       processed or there is not enough data remaining
       in the block to satisfy the format string.

       If, either as a result of user specification or
       hexdump modifying the iteration count as
       described above, an iteration count is greater
       than one, no trailing whitespace characters are
       output during the last iteration.

       It is an error to specify a byte count as well as
       multiple conversion characters or strings unless
       all but one of the conversion characters or
       strings is _a or _A.

       If, as a result of the specification of the -n
       option or end-of-file being reached, input data
       only partially satisfies a format string, the
       input block is zero-padded sufficiently to
       display all available data (i.e., any format
       units overlapping the end of data will display
       some number of the zero bytes).

       Further output by such format strings is replaced
       by an equivalent number of spaces. An equivalent
       number of spaces is defined as the number of
       spaces output by an s conversion character with
       the same field width and precision as the
       original conversion character or conversion
       string but with any '+', ' ', '#' conversion flag
       characters removed, and referencing a NULL

       If no format strings are specified, the default
       display is very similar to the -x output format
       (the -x option causes more space to be used
       between format units than in the default output).

EXIT STATUS         top

       hexdump exits 0 on success and > 0 if an error

CONFORMING TO         top

       The hexdump utility is expected to be IEEE Std
       1003.2 ("POSIX.2") compatible.

EXAMPLES         top

       Display the input in perusal format:

              "%06.6_ao "  12/1 "%3_u "
              "\t" "%_p "

       Implement the -x option:

              "%07.7_ax  " 8/2 "%04x " "\n"

       MBR Boot Signature example: Highlight the
       addresses cyan and the bytes at offsets 510 and
       511 green if their value is 0xAA55, red

              "%07.7_ax_L[cyan]  " 8/2 "   %04x_L[green:0xAA55@510-511,!red:0xAA55@510-511] " "\n"

COLORS         top

       The output colorization is implemented by
       terminal-colors.d(5) functionality. Implicit
       coloring can be disabled by an empty file


       for the hexdump command or for all tools by


       The user-specific
       $XDG_CONFIG_HOME/terminal-colors.d or
       $HOME/.config/terminal-colors.d overrides the
       global setting.

       Note that the output colorization may be enabled
       by default, and in this case terminal-colors.d
       directories do not have to exist yet.

REPORTING BUGS         top

       For bug reports, use the issue tracker at

AVAILABILITY         top

       The hexdump command is part of the util-linux
       package which can be downloaded from Linux Kernel
       This page is part of the util-linux (a random
       collection of Linux utilities) project.
       Information about the project can be found at 
       If you have a bug report for this manual page,
       send it to util-linux@vger.kernel.org. This page
       was obtained from the project's upstream Git
       on 2023-12-22. (At that time, the date of the
       most recent commit that was found in the
       repository was 2023-12-14.) If you discover any
       rendering problems in this HTML version of the
       page, or you believe there is a better or more
       up-to-date source for the page, or you have
       corrections or improvements to the information in
       this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

util-linux 2.39.594-1e0ad      2023-07-19                     HEXDUMP(1)