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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 each specified file, or
     the standard input if no file arguments 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

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

     -v          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 containing a single asterisk (`*').

     -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 line.

     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

     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:

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

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

     _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   07F del

     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, four and eight
                                   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

     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 `+', ` ', and `#' conversion flag characters removed, and
     referencing a NULL string.

     If no format strings are specified, the default display is equivalent to
     specifying the -x option.

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

     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"


NetBSD 10.99                     June 24, 2012                    NetBSD 10.99