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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 hexadecimal, followed by six-
	      teen space-separated, three-column, zero-filled bytes of input data, in octal,  per
	      line.

       -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.

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

       -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.

       -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 pre-
	      ceding group of output lines (except for the input offsets), are	replaced  with	a
	      line comprised of 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, transform-
       ing 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 white-
       space before or after the slash is ignored.

       The format is required and must be surrounded by double quote (" ") marks.  It  is  inter-
       preted 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  unspeci-
	      fied).

       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 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  deci-
	      mal, 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  dis-
	      played  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  dis-
	      played as a single '.'.

       _u     Output  US  ASCII  characters,  with the exception that control characters are dis-
	      played using the following, lower-case, names.  Characters greater than 0xff, hexa-
	      decimal, 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 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 sat-
       isfy 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 dis-
       play 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 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") compatible.

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)
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