1.\" Copyright (c) 1989, 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)hexdump.1 8.2 (Berkeley) 4/18/94 33.\" 34.Dd April 18, 1994 35.Dt HEXDUMP 1 36.Os 37.Sh NAME 38.Nm hexdump, hd 39.Nd ascii, decimal, hexadecimal, octal dump 40.Sh SYNOPSIS 41.Nm hexdump 42.Op Fl bcCdovx 43.Op Fl e Ar format_string 44.Op Fl f Ar format_file 45.Op Fl n Ar length 46.Bk -words 47.Op Fl s Ar skip 48.Ek 49.Ar file ... 50.Nm hd 51.Op Fl bcdovx 52.Op Fl e Ar format_string 53.Op Fl f Ar format_file 54.Op Fl n Ar length 55.Bk -words 56.Op Fl s Ar skip 57.Ek 58.Ar file ... 59.Sh DESCRIPTION 60The hexdump utility is a filter which displays the specified files, or 61the standard input, if no files are specified, in a user specified 62format. 63.Pp 64The options are as follows: 65.Bl -tag -width Fl 66.It Fl b 67.Em One-byte octal display . 68Display the input offset in hexadecimal, followed by sixteen 69space-separated, three column, zero-filled, bytes of input data, 70in octal, per line. 71.It Fl c 72.Em One-byte character display . 73Display the input offset in hexadecimal, followed by sixteen 74space-separated, three column, space-filled, characters of input 75data per line. 76.It Fl C 77.Em Canonical hex+ASCII display. 78Display the input offset in hexadecimal, followed by sixteen 79space-separated, two column, hexadecimal bytes, followed by the 80same sixteen bytes in %_p format enclosed in ``|'' characters. 81.Pp 82Calling the command 83.Nm hd 84implies this option. 85.It Fl d 86.Em Two-byte decimal display. 87Display the input offset in hexadecimal, followed by eight 88space-separated, five column, zero-filled, two-byte units 89of input data, in unsigned decimal, per line. 90.It Fl e Ar format_string 91Specify a format string to be used for displaying data. 92.It Fl f Ar format_file 93Specify a file that contains one or more newline separated format strings. 94Empty lines and lines whose first non-blank character is a hash mark 95.Pf ( Cm \&# ) 96are ignored. 97.It Fl n Ar length 98Interpret only 99.Ar length 100bytes of input. 101.It Fl o 102.Em Two-byte octal display. 103Display the input offset in hexadecimal, followed by eight 104space-separated, six column, zero-filled, two byte quantities of 105input data, in octal, per line. 106.It Fl s Ar offset 107Skip 108.Ar offset 109bytes from the beginning of the input. 110By default, 111.Ar offset 112is interpreted as a decimal number. 113With a leading 114.Cm 0x 115or 116.Cm 0X , 117.Ar offset 118is interpreted as a hexadecimal number, 119otherwise, with a leading 120.Cm 0 , 121.Ar offset 122is interpreted as an octal number. 123Appending the character 124.Cm b , 125.Cm k , 126or 127.Cm m 128to 129.Ar offset 130causes it to be interpreted as a multiple of 131.Li 512 , 132.Li 1024 , 133or 134.Li 1048576 , 135respectively. 136.It Fl v 137The 138.Fl v 139option causes hexdump to display all input data. 140Without the 141.Fl v 142option, any number of groups of output lines, which would be 143identical to the immediately preceding group of output lines (except 144for the input offsets), are replaced with a line comprised of a 145single asterisk. 146.It Fl x 147.Em Two-byte hexadecimal display. 148Display the input offset in hexadecimal, followed by eight, space 149separated, four column, zero-filled, two-byte quantities of input 150data, in hexadecimal, per line. 151.El 152.Pp 153For each input file, 154.Nm hexdump 155sequentially copies the input to standard output, transforming the 156data according to the format strings specified by the 157.Fl e 158and 159.Fl f 160options, in the order that they were specified. 161.Ss Formats 162A format string contains any number of format units, separated by 163whitespace. 164A format unit contains up to three items: an iteration count, a byte 165count, and a format. 166.Pp 167The iteration count is an optional positive integer, which defaults to 168one. 169Each format is applied iteration count times. 170.Pp 171The byte count is an optional positive integer. 172If specified it defines the number of bytes to be interpreted by 173each iteration of the format. 174.Pp 175If an iteration count and/or a byte count is specified, a single slash 176must be placed after the iteration count and/or before the byte count 177to disambiguate them. 178Any whitespace before or after the slash is ignored. 179.Pp 180The format is required and must be surrounded by double quote 181(" ") marks. 182It is interpreted as a fprintf-style format string (see 183.Xr fprintf 3 ) , 184with the 185following exceptions: 186.Bl -bullet -offset indent 187.It 188An asterisk (*) may not be used as a field width or precision. 189.It 190A byte count or field precision 191.Em is 192required for each ``s'' conversion 193character (unlike the 194.Xr fprintf 3 195default which prints the entire string if the precision is unspecified). 196.It 197The conversion characters ``h'', ``l'', ``n'', ``p'' and ``q'' are 198not supported. 199.It 200The single character escape sequences 201described in the C standard are supported: 202.Bd -ragged -offset indent -compact 203.Bl -column <alert_character> 204.It NUL \e0 205.It <alert character> \ea 206.It <backspace> \eb 207.It <form-feed> \ef 208.It <newline> \en 209.It <carriage return> \er 210.It <tab> \et 211.It <vertical tab> \ev 212.El 213.Ed 214.El 215.Pp 216Hexdump also supports the the following additional conversion strings: 217.Bl -tag -width Fl 218.It Cm \&_a Ns Op Cm dox 219Display the input offset, cumulative across input files, of the 220next byte to be displayed. 221The appended characters 222.Cm d , 223.Cm o , 224and 225.Cm x 226specify the display base 227as decimal, octal or hexadecimal respectively. 228.It Cm \&_A Ns Op Cm dox 229Identical to the 230.Cm \&_a 231conversion string except that it is only performed 232once, when all of the input data has been processed. 233.It Cm \&_c 234Output characters in the default character set. 235Nonprinting characters are displayed in three character, zero-padded 236octal, except for those representable by standard escape notation 237(see above), 238which are displayed as two character strings. 239.It Cm _p 240Output characters in the default character set. 241Nonprinting characters are displayed as a single 242.Dq Cm \&. . 243.It Cm _u 244Output US ASCII characters, with the exception that control characters are 245displayed using the following, lower-case, names. 246Characters greater than 0xff, hexadecimal, are displayed as hexadecimal 247strings. 248.Bl -column \&000_nu \&001_so \&002_st \&003_et \&004_eo 249.It \&000\ nul\t001\ soh\t002\ stx\t003\ etx\t004\ eot\t005\ enq 250.It \&006\ ack\t007\ bel\t008\ bs\t009\ ht\t00A\ lf\t00B\ vt 251.It \&00C\ ff\t00D\ cr\t00E\ so\t00F\ si\t010\ dle\t011\ dc1 252.It \&012\ dc2\t013\ dc3\t014\ dc4\t015\ nak\t016\ syn\t017\ etb 253.It \&018\ can\t019\ em\t01A\ sub\t01B\ esc\t01C\ fs\t01D\ gs 254.It \&01E\ rs\t01F\ us\t0FF\ del 255.El 256.El 257.Pp 258The default and supported byte counts for the conversion characters 259are as follows: 260.Bl -tag -width "Xc,_Xc,_Xc,_Xc,_Xc,_Xc" -offset indent 261.It Li \&%_c , \&%_p , \&%_u , \&%c 262One byte counts only. 263.It Xo 264.Li \&%d , \&%i , \&%o , 265.Li \&%u , \&%X , \&%x 266.Xc 267Four byte default, one, two and four byte counts supported. 268.It Xo 269.Li \&%E , \&%e , \&%f , 270.Li \&%G , \&%g 271.Xc 272Eight byte default, four byte counts supported. 273.El 274.Pp 275The amount of data interpreted by each format string is the sum of the 276data required by each format unit, which is the iteration count times the 277byte count, or the iteration count times the number of bytes required by 278the format if the byte count is not specified. 279.Pp 280The input is manipulated in ``blocks'', where a block is defined as the 281largest amount of data specified by any format string. 282Format strings interpreting less than an input block's worth of data, 283whose last format unit both interprets some number of bytes and does 284not have a specified iteration count, have the iteration count 285incremented until the entire input block has been processed or there 286is not enough data remaining in the block to satisfy the format string. 287.Pp 288If, either as a result of user specification or hexdump modifying 289the iteration count as described above, an iteration count is 290greater than one, no trailing whitespace characters are output 291during the last iteration. 292.Pp 293It is an error to specify a byte count as well as multiple conversion 294characters or strings unless all but one of the conversion characters 295or strings is 296.Cm \&_a 297or 298.Cm \&_A . 299.Pp 300If, as a result of the specification of the 301.Fl n 302option or end-of-file being reached, input data only partially 303satisfies a format string, the input block is zero-padded sufficiently 304to display all available data (i.e. any format units overlapping the 305end of data will display some number of the zero bytes). 306.Pp 307Further output by such format strings is replaced by an equivalent 308number of spaces. 309An equivalent number of spaces is defined as the number of spaces 310output by an 311.Cm s 312conversion character with the same field width 313and precision as the original conversion character or conversion 314string but with any 315.Dq Li \&+ , 316.Dq \&\ \& , 317.Dq Li \&# 318conversion flag characters 319removed, and referencing a NULL string. 320.Pp 321If no format strings are specified, the default display is equivalent 322to specifying the 323.Fl x 324option. 325.Pp 326.Nm hexdump 327exits 0 on success and >0 if an error occurred. 328.Sh EXAMPLES 329Display the input in perusal format: 330.Bd -literal -offset indent 331"%06.6_ao " 12/1 "%3_u " 332"\et\et" "%_p " 333"\en" 334.Ed 335.Pp 336Implement the \-x option: 337.Bd -literal -offset indent 338"%07.7_Ax\en" 339"%07.7_ax " 8/2 "%04x " "\en" 340.Ed 341.Sh SEE ALSO 342.Xr gdb 1 343