1.\" $OpenBSD: hexdump.1,v 1.19 2007/05/31 19:20:11 jmc Exp $ 2.\" $NetBSD: hexdump.1,v 1.14 2001/12/07 14:46:24 bjh21 Exp $ 3.\" 4.\" Copyright (c) 1989, 1990, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" from: @(#)hexdump.1 8.2 (Berkeley) 4/18/94 32.\" 33.Dd $Mdocdate: May 31 2007 $ 34.Dt HEXDUMP 1 35.Os 36.Sh NAME 37.Nm hexdump 38.Nd ascii, decimal, hexadecimal, octal dump 39.Sh SYNOPSIS 40.Nm hexdump 41.Bk -words 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.Op Fl s Ar offset 47.Op Ar 48.Ek 49.Sh DESCRIPTION 50The 51.Nm 52utility is a filter which displays the specified files, or 53the standard input, if no files are specified, in a user-specified 54format. 55.Pp 56The options are as follows: 57.Bl -tag -width Ds 58.It Fl b 59.Em One-byte octal display . 60Display the input offset in hexadecimal, followed by sixteen 61space-separated, three column, zero-filled, bytes of input data, 62in octal, per line. 63.It Fl C 64.Em Canonical hex+ASCII display . 65Display the input offset in hexadecimal, followed by sixteen 66space-separated, two column, hexadecimal bytes, followed by the 67same sixteen bytes in %_p format enclosed in ``|'' characters. 68.It Fl c 69.Em One-byte character display . 70Display the input offset in hexadecimal, followed by sixteen 71space-separated, three column, space-filled, characters of input 72data per line. 73.It Fl d 74.Em Two-byte decimal display . 75Display the input offset in hexadecimal, followed by eight 76space-separated, five column, zero-filled, two-byte units 77of input data, in unsigned decimal, per line. 78.It Fl e Ar format_string 79Specify a format string to be used for displaying data. 80.It Fl f Ar format_file 81Specify a file that contains one or more newline separated format strings. 82Empty lines and lines whose first non-blank character is a hash mark 83.Pq Ql # 84are ignored. 85.It Fl n Ar length 86Interpret only 87.Ar length 88bytes of input. 89By default, 90.Ar length 91is interpreted as a decimal number. 92With a leading 93.Cm 0x 94or 95.Cm 0X , 96.Ar length 97is interpreted as a hexadecimal number, 98otherwise, with a leading 99.Cm 0 , 100.Ar length 101is interpreted as an octal number. 102.It Fl o 103.Em Two-byte octal display . 104Display the input offset in hexadecimal, followed by eight 105space-separated, six column, zero-filled, two byte quantities of 106input data, in octal, per line. 107.It Fl s Ar offset 108Skip 109.Ar offset 110bytes from the beginning of the input. 111By default, 112.Ar offset 113is interpreted as a decimal number. 114With a leading 115.Cm 0x 116or 117.Cm 0X , 118.Ar offset 119is interpreted as a hexadecimal number, 120otherwise, with a leading 121.Cm 0 , 122.Ar offset 123is interpreted as an octal number. 124Appending the character 125.Cm b , 126.Cm k , 127or 128.Cm m 129to 130.Ar offset 131causes it to be interpreted as a multiple of 132.Li 512 , 133.Li 1024 , 134or 135.Li 1048576 , 136respectively. 137.It Fl v 138The 139.Fl v 140option causes hexdump to display all input data. 141Without the 142.Fl v 143option, any number of groups of output lines, which would be 144identical to the immediately preceding group of output lines (except 145for the input offsets), are replaced with a line comprised of a 146single asterisk 147.Pq Ql * . 148.It Fl x 149.Em Two-byte hexadecimal display . 150Display the input offset in hexadecimal, followed by eight, space 151separated, four column, zero-filled, two-byte quantities of input 152data, in hexadecimal, per line. 153.El 154.Pp 155For each input file, 156.Nm 157sequentially copies the input to standard output, transforming the 158data according to the format strings specified by the 159.Fl e 160and 161.Fl f 162options, in the order that they were specified. 163.Ss Formats 164A format string contains any number of format units, separated by 165whitespace. 166A format unit contains up to three items: an iteration count, a byte 167count, and a format. 168.Pp 169The iteration count is an optional positive integer, which defaults to 170one. 171Each format is applied iteration count times. 172.Pp 173The byte count is an optional positive integer. 174If specified it defines the number of bytes to be interpreted by 175each iteration of the format. 176.Pp 177If an iteration count and/or a byte count is specified, a single slash 178.Pq Sq / 179must be placed after the iteration count and/or before the byte count 180to disambiguate them. 181Any whitespace before or after the slash is ignored. 182.Pp 183The format is required and must be surrounded by double quote 184.Pq \&"\& \&" 185marks. 186It is interpreted as a fprintf-style format string (see 187.Xr fprintf 3 ) , 188with the 189following exceptions: 190.Bl -bullet -offset indent 191.It 192An asterisk (*) may not be used as a field width or precision. 193.It 194A byte count or field precision 195.Em is 196required for each 197.Sq s 198conversion character (unlike the 199.Xr fprintf 3 200default which prints the entire string if the precision is unspecified). 201.It 202The conversion characters 203.Sq h , 204.Sq l , 205.Sq n , 206.Sq p , 207and 208.Sq q 209are not supported. 210.It 211The single character escape sequences 212described in the C standard are supported: 213.Pp 214.Bl -tag -width "Xalert characterXXX" -offset indent -compact 215.It NUL 216\e0 217.It Aq alert character 218\ea 219.It Aq backspace 220\eb 221.It Aq form-feed 222\ef 223.It Aq newline 224\en 225.It Aq carriage return 226\er 227.It Aq tab 228\et 229.It Aq vertical tab 230\ev 231.El 232.El 233.Pp 234.Nm 235also supports the following additional conversion strings: 236.Bl -tag -width Fl 237.It Cm \&_a Ns Op Cm dox 238Display the input offset, cumulative across input files, of the 239next byte to be displayed. 240The appended characters 241.Cm d , 242.Cm o , 243and 244.Cm x 245specify the display base 246as decimal, octal or hexadecimal respectively. 247.It Cm \&_A Ns Op Cm dox 248Identical to the 249.Cm \&_a 250conversion string except that it is only performed 251once, when all of the input data has been processed. 252.It Cm \&_c 253Output characters in the default character set. 254Nonprinting characters are displayed in three character, zero-padded 255octal, except for those representable by standard escape notation 256(see above), 257which are displayed as two character strings. 258.It Cm _p 259Output characters in the default character set. 260Nonprinting characters are displayed as a single dot 261.Ql \&. . 262.It Cm _u 263Output US ASCII characters, with the exception that control characters are 264displayed using the following, lower-case, names. 265Characters greater than 0xff, hexadecimal, are displayed as hexadecimal 266strings. 267.Bl -column \&000_nu \&001_so \&002_st \&003_et \&004_eo 268.It \&000\ nul\t001\ soh\t002\ stx\t003\ etx\t004\ eot\t005\ enq 269.It \&006\ ack\t007\ bel\t008\ bs\t009\ ht\t00A\ lf\t00B\ vt 270.It \&00C\ ff\t00D\ cr\t00E\ so\t00F\ si\t010\ dle\t011\ dc1 271.It \&012\ dc2\t013\ dc3\t014\ dc4\t015\ nak\t016\ syn\t017\ etb 272.It \&018\ can\t019\ em\t01A\ sub\t01B\ esc\t01C\ fs\t01D\ gs 273.It \&01E\ rs\t01F\ us\t0FF\ del 274.El 275.El 276.Pp 277The default and supported byte counts for the conversion characters 278are as follows: 279.Bl -tag -width "Xc,_Xc,_Xc,_Xc,_Xc,_Xc" -offset indent 280.It Li \&%_c , \&%_p , \&%_u , \&%c 281One byte counts only. 282.It Xo 283.Li \&%d , \&%i , \&%o , 284.Li \&%u , \&%X , \&%x 285.Xc 286Four byte default, one, two, four and eight byte counts supported. 287.It Xo 288.Li \&%E , \&%e , \&%f , 289.Li \&%G , \&%g 290.Xc 291Eight byte default, four byte counts supported. 292.El 293.Pp 294The amount of data interpreted by each format string is the sum of the 295data required by each format unit, which is the iteration count times the 296byte count, or the iteration count times the number of bytes required by 297the format if the byte count is not specified. 298.Pp 299The input is manipulated in 300.Dq blocks , 301where a block is defined as the 302largest amount of data specified by any format string. 303Format strings interpreting less than an input block's worth of data, 304whose last format unit both interprets some number of bytes and does 305not have a specified iteration count, have the iteration count 306incremented until the entire input block has been processed or there 307is not enough data remaining in the block to satisfy the format string. 308.Pp 309If, either as a result of user specification or hexdump modifying 310the iteration count as described above, an iteration count is 311greater than one, no trailing whitespace characters are output 312during the last iteration. 313.Pp 314It is an error to specify a byte count as well as multiple conversion 315characters or strings unless all but one of the conversion characters 316or strings is 317.Cm \&_a 318or 319.Cm \&_A . 320.Pp 321If, as a result of the specification of the 322.Fl n 323option or end-of-file being reached, input data only partially 324satisfies a format string, the input block is zero-padded sufficiently 325to display all available data (i.e., any format units overlapping the 326end of data will display some number of the zero bytes). 327.Pp 328Further output by such format strings is replaced by an equivalent 329number of spaces. 330An equivalent number of spaces is defined as the number of spaces 331output by an 332.Cm s 333conversion character with the same field width 334and precision as the original conversion character or conversion 335string but with any 336.Ql + , 337.Ql \&\ \& , 338.Ql # 339conversion flag characters 340removed, and referencing a NULL string. 341.Pp 342If no format strings are specified, the default display is equivalent 343to specifying the 344.Fl x 345option. 346.Pp 347.Ex -std hexdump 348.Sh EXAMPLES 349Display the input in perusal format: 350.Bd -literal -offset indent 351"%06.6_ao " 12/1 "%3_u " 352"\et\et" "%_p " 353"\en" 354.Ed 355.Pp 356Implement the \-x option: 357.Bd -literal -offset indent 358"%07.7_Ax\en" 359"%07.7_ax " 8/2 "%04x " "\en" 360.Ed 361.Sh SEE ALSO 362.Xr od 1 363