HEXDUMP(1)			 User Commands			    HEXDUMP(1)



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

SYNOPSIS
       hexdump [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
       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  display.	 Display the input offset in hexadeci-
	      mal, followed by sixteen	space-separated,  three-column,	 zero-
	      filled bytes of input data, in octal, per line.

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

       -C     Canonical	 hex+ASCII display.  Display the input offset in hexa-
	      decimal, followed by sixteen space-separated, two-column,	 hexa-
	      decimal  bytes, followed by the same sixteen bytes in %_p format
	      enclosed in '|' characters.

       -d     Two-byte decimal display.	 Display the input offset in hexadeci-
	      mal,  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 for-
	      mat strings.  Empty lines and lines whose first non-blank	 char-
	      acter is a hash mark (#) are ignored.

       -n length
	      Interpret only length bytes of input.

       -o     Two-byte	octal  display.	 Display the input offset in hexadeci-
	      mal, 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.

       -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  com-
	      prised of a single asterisk.

       -x     Two-byte hexadecimal display.  Display the input offset in hexa-
	      decimal, 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.

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  conver-
	      sion  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	 stan-
	      dard 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.

       _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 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  default character set.  Nonprinting
	      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

   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 for-
       mat unit both interprets some number of bytes and does not have a spec-
       ified  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 iter-
       ation.

       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 num-
       ber 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 ref-
       erencing a NULL string.

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

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

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

       Implement the -x option:
	  "%07.7_Ax\n"
	  "%07.7_ax  " 8/2 "%04x " "\n"

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

AVAILABILITY
       The  hexdump command is part of the util-linux package and is available
       from Linux Kernel  Archive  <ftp://ftp.kernel.org/pub/linux/utils/util-
       linux/>.



util-linux			September 2011			    HEXDUMP(1)