HEXDUMP(1)                   General Commands Manual                  HEXDUMP(1)

     hexdump – ASCII, decimal, hexadecimal, octal dump

     hexdump [-bcCdovx] [-e format_string] [-f format_file] [-n length]
             [-s skip] file ...

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

     The options are as follows:

     -b      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      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.

     -c      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.

     -d      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_string
             Specify a format string to be used for displaying data.

     -f format_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.

     -n length
             Interpret only length bytes of input.

     -o      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 offset
             Skip offset bytes from the beginning of the input.  By default,
             offset is interpreted as a decimal number.  With a leading 0x or
             0X, offset is interpreted as a hexadecimal number, otherwise, with
             a leading 0, offset is interpreted as an octal number.  Appending
             the character b, k, m, or g to offset causes it to be interpreted
             as a multiple of 512, 1024, 1048576, or 1073741824, respectively.

     -v      Cause 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

     -x      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

     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.

     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 precision.

           •   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 supported.

           •   The single character escape sequences described in the C standard
               are supported:

                     NUL                  \0
                     <alert character>    \a
                     <backspace>          \b
                     <form-feed>          \f
                     <newline>            \n
                     <carriage return>    \r
                     <tab>                \t
                     <vertical tab>       \v

     The hexdump utility also supports the following additional conversion

     Cm _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

     _A[dox]     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.  Nonprinting
                 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 ASCII character set.  Non-ASCII
                 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 NUL001 SOH002 STX003 ETX004 EOT005 ENQ
                 006 ACK007 BEL008 BS009 HT00A LF00B VT
                 00C FF00D CR00E SO00F SI010 DLE011 DC1
                 012 DC2013 DC3014 DC4015 NAK016 SYN017 ETB
                 018 CAN019 EM01A SUB01B ESC01C FS01D GS
                 01E RS01F US0FF DEL

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

           %_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 and twelve 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 a one-byte
     hexadecimal display.

     The hexdump utility exits 0 on success, and >0 if an error occurs.

     Note that the following format strings, used with -e, must be enclosed in
     single quotes.

     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"

     gdb(1), od(1)

macOS 12.1                        July 10, 2004                       macOS 12.1