hexdump(1) — Linux manual page


HEXDUMP(1)                      User Commands                     HEXDUMP(1)

NAME         top

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

SYNOPSIS         top

       hexdump [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

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 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.

       -V, --version
              Display version information and exit.

       -h, --help
              Display help text 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:

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

       2.     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).

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

       4.     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

              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.

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

       _c     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

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

       _u     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 offset.

       COLOR  One of the 8 basic shell colors.

       VALUE  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 color_units.

       OFFSET 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 supported.

       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

       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 string.

       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 occurred.

CONFORMING TO         top

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

EXAMPLES         top

       Display the input in perusal format:
          "%06.6_ao "  12/1 "%3_u "
          "\t\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

       Implicit coloring can be disabled by an empty file /etc/terminal-

       See terminal-colors.d(5) for more details about colorization

AVAILABILITY         top

       The hexdump command is part of the util-linux package and is
       available from Linux Kernel Archive 

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.  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 repository
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2020-09-18.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-09-15.)  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

util-linux                       April 2013                       HEXDUMP(1)