# hexdump

## NAME



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


## SYNOPSIS



           **hexdump**[options] _file_ ...
    
           **hd**[options] _file_ ...
    


## DESCRIPTION



           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



           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.
    
           **-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
               line.
    
           **-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**
               Display 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



           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:
    
                      \0   NULL
                      \a   alert character
                      \b   backspace
                      \f   form-feed
                      \n   newline
                      \r   carriage return
                      \t   tab
                      \v   vertical tab
    
       **Conversion strings**
           The **hexdump** utility also supports the following additional
           conversion strings.
    
           **_a[dox]**
               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.
    
           **_A[dox]**
               Almost 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
               strings.
    
           **_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.
    
                      00 nul     08 bs      10 dle     18 can     7F del
                      01 soh     09 ht      11 dc1     19 em
                      02 stx     0A lf      12 dc2     1A sub
                      03 etx     0B vt      13 dc3     1B esc
                      04 eot     0C ff      14 dc4     1C fs
                      05 enq     0D cr      15 nak     1D gs
                      06 ack     0E so      16 syn     1E rs
                      07 bel     0F si      17 etb     1F us
    
       **Colors**
           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.
    
           **_L[color_unit_1,color_unit_2,...,color_unit_n]**
    
           The full syntax of a color unit is as follows:
    
           **[!]COLOR[:VALUE][@OFFSET_START[-END]]**
    
           **!**
               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
               offset.
    
       **Counters**
           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 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 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



           **hexdump** exits 0 on success and > 0 if an error occurred.
    


## CONFORMING TO



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


## EXAMPLES



           Display the input in perusal format:
    
                  "%06.6_ao "  12/1 "%3_u "
                  "\t" "%_p "
                  "\n"
    
           Implement the **-x** option:
    
                  "%07.7_Ax\n"
                  "%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
           otherwise.
    
                  "%07.7_Ax_L[cyan]\n"
                  "%07.7_ax_L[cyan]  " 8/2 "   %04x_L[green:0xAA55@510-511,!red:0xAA55@510-511] " "\n"
    


## COLORS



           The output colorization is implemented by terminal-colors.d(5)
           functionality. Implicit coloring can be disabled by an empty file
    
              _/etc/terminal-colors.d/hexdump.disable_
    
           for the **hexdump** command or for all tools by
    
              _/etc/terminal-colors.d/disable_
    
           Since version 2.41, the $NO_COLOR environment variable is also
           supported to disable output colorization unless explicitly enabled
           by a command-line option.
    
           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.
    


## AVAILABILITY



           The **hexdump** command is part of the util-linux package which can be
           downloaded from Linux Kernel Archive
           <https://www.kernel.org/pub/linux/utils/util-linux/>. 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
           2025-08-11. (At that time, the date of the most recent commit that
           was found in the repository was 2025-08-05.) 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 2.42-start-521-ec46  2025-08-09                     _HEXDUMP_(1)
    


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