hexdump.1 (11021B)
1 .\" $OpenBSD: hexdump.1,v 1.24 2011/05/06 18:11:43 otto 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 6 2011 $ 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 50 The 51 .Nm 52 utility is a filter which displays the specified files, or 53 the standard input, if no files are specified, in a user-specified 54 format. 55 .Pp 56 The options are as follows: 57 .Bl -tag -width Ds 58 .It Fl b 59 .Em One-byte octal display . 60 Display the input offset in hexadecimal, followed by sixteen 61 space-separated, three column, zero-filled, bytes of input data, 62 in octal, per line. 63 .It Fl C 64 .Em Canonical hex+ASCII display . 65 Display the input offset in hexadecimal, followed by sixteen 66 space-separated, two column, hexadecimal bytes, followed by the 67 same sixteen bytes in %_p format enclosed in ``|'' characters. 68 .It Fl c 69 .Em One-byte character display . 70 Display the input offset in hexadecimal, followed by sixteen 71 space-separated, three column, space-filled, characters of input 72 data per line. 73 .It Fl d 74 .Em Two-byte decimal display . 75 Display the input offset in hexadecimal, followed by eight 76 space-separated, five column, zero-filled, two-byte units 77 of input data, in unsigned decimal, per line. 78 .It Fl e Ar format_string 79 Specify a format string to be used for displaying data. 80 .It Fl f Ar format_file 81 Specify a file that contains one or more newline separated format strings. 82 Empty lines and lines whose first non-blank character is a hash mark 83 .Pq Ql # 84 are ignored. 85 .It Fl n Ar length 86 Interpret only 87 .Ar length 88 bytes of input. 89 By default, 90 .Ar length 91 is interpreted as a decimal number. 92 With a leading 93 .Cm 0x 94 or 95 .Cm 0X , 96 .Ar length 97 is interpreted as a hexadecimal number, 98 otherwise, with a leading 99 .Cm 0 , 100 .Ar length 101 is interpreted as an octal number. 102 .It Fl o 103 .Em Two-byte octal display . 104 Display the input offset in hexadecimal, followed by eight 105 space-separated, six column, zero-filled, two byte quantities of 106 input data, in octal, per line. 107 .It Fl s Ar offset 108 Skip 109 .Ar offset 110 bytes from the beginning of the input. 111 By default, 112 .Ar offset 113 is interpreted as a decimal number. 114 With a leading 115 .Cm 0x 116 or 117 .Cm 0X , 118 .Ar offset 119 is interpreted as a hexadecimal number, 120 otherwise, with a leading 121 .Cm 0 , 122 .Ar offset 123 is interpreted as an octal number. 124 Appending the character 125 .Cm b , 126 .Cm k , 127 or 128 .Cm m 129 to 130 .Ar offset 131 causes it to be interpreted as a multiple of 132 .Li 512 , 133 .Li 1024 , 134 or 135 .Li 1048576 , 136 respectively. 137 .It Fl v 138 The 139 .Fl v 140 option causes hexdump to display all input data. 141 Without the 142 .Fl v 143 option, any number of groups of output lines, which would be 144 identical to the immediately preceding group of output lines (except 145 for the input offsets), are replaced with a line comprised of a 146 single asterisk 147 .Pq Ql * . 148 .It Fl x 149 .Em Two-byte hexadecimal display . 150 Display the input offset in hexadecimal, followed by eight, space 151 separated, four column, zero-filled, two-byte quantities of input 152 data, in hexadecimal, per line. 153 .El 154 .Pp 155 For each input file, 156 .Nm 157 sequentially copies the input to standard output, transforming the 158 data according to the format strings specified by the 159 .Fl e 160 and 161 .Fl f 162 options, in the order that they were specified. 163 .Ss Formats 164 A format string contains any number of format units, separated by 165 whitespace. 166 A format unit contains up to three items: an iteration count, a byte 167 count, and a format. 168 .Pp 169 The iteration count is an optional positive integer, which defaults to 170 one. 171 Each format is applied iteration count times. 172 .Pp 173 The byte count is an optional positive integer. 174 If specified it defines the number of bytes to be interpreted by 175 each iteration of the format. 176 .Pp 177 If an iteration count and/or a byte count is specified, a single slash 178 .Pq Sq / 179 must be placed after the iteration count and/or before the byte count 180 to disambiguate them. 181 Any whitespace before or after the slash is ignored. 182 .Pp 183 The format is required and must be surrounded by double quote 184 .Pq \&"\& \&" 185 marks 186 (the quote mark is a special character in many shell programs, 187 and may have to be escaped from the shell). 188 It is interpreted as a fprintf-style format string (see 189 .Xr fprintf 3 ) , 190 with the 191 following exceptions: 192 .Bl -bullet -offset indent 193 .It 194 An asterisk (*) may not be used as a field width or precision. 195 .It 196 A byte count or field precision 197 .Em is 198 required for each 199 .Sq s 200 conversion character (unlike the 201 .Xr fprintf 3 202 default which prints the entire string if the precision is unspecified). 203 .It 204 The conversion characters 205 .Sq h , 206 .Sq l , 207 .Sq n , 208 .Sq p , 209 and 210 .Sq q 211 are not supported. 212 .It 213 The single character escape sequences 214 described in the C standard are supported: 215 .Pp 216 .Bl -tag -width "Xalert characterXXX" -offset indent -compact 217 .It NUL 218 \e0 219 .It Aq alert character 220 \ea 221 .It Aq backspace 222 \eb 223 .It Aq form-feed 224 \ef 225 .It Aq newline 226 \en 227 .It Aq carriage return 228 \er 229 .It Aq tab 230 \et 231 .It Aq vertical tab 232 \ev 233 .El 234 .El 235 .Pp 236 .Nm 237 also supports the following additional conversion strings: 238 .Bl -tag -width Fl 239 .It Cm \&_a Ns Op Cm dox 240 Display the input offset, cumulative across input files, of the 241 next byte to be displayed. 242 The appended characters 243 .Cm d , 244 .Cm o , 245 and 246 .Cm x 247 specify the display base 248 as decimal, octal or hexadecimal respectively. 249 .It Cm \&_A Ns Op Cm dox 250 Identical to the 251 .Cm \&_a 252 conversion string except that it is only performed 253 once, when all of the input data has been processed. 254 .It Cm \&_c 255 Output characters in the default character set. 256 Nonprinting characters are displayed in three character, zero-padded 257 octal, except for those representable by standard escape notation 258 (see above), 259 which are displayed as two character strings. 260 .It Cm _p 261 Output characters in the default character set. 262 Nonprinting characters are displayed as a single dot 263 .Ql \&. . 264 .It Cm _u 265 Output US ASCII characters, with the exception that control characters are 266 displayed using the following, lower-case, names. 267 Other non-printable characters are displayed as hexadecimal strings. 268 .Bd -literal -offset 3n 269 000 nul 001 soh 002 stx 003 etx 004 eot 005 enq 270 006 ack 007 bel 008 bs 009 ht 00A lf 00B vt 271 00C ff 00D cr 00E so 00F si 010 dle 011 dc1 272 012 dc2 013 dc3 014 dc4 015 nak 016 syn 017 etb 273 018 can 019 em 01A sub 01B esc 01C fs 01D gs 274 01E rs 01F us 07F del 275 .Ed 276 .El 277 .Pp 278 The default and supported byte counts for the conversion characters 279 are as follows: 280 .Bl -tag -width "Xc,_Xc,_Xc,_Xc,_Xc,_Xc" -offset indent 281 .It Li \&%_c , \&%_p , \&%_u , \&%c 282 One byte counts only. 283 .It Xo 284 .Li \&%d , \&%i , \&%o , 285 .Li \&%u , \&%X , \&%x 286 .Xc 287 Four byte default, one, two, four and eight byte counts supported. 288 .It Xo 289 .Li \&%E , \&%e , \&%f , 290 .Li \&%G , \&%g 291 .Xc 292 Eight byte default, four byte counts supported. 293 .El 294 .Pp 295 The amount of data interpreted by each format string is the sum of the 296 data required by each format unit, which is the iteration count times the 297 byte count, or the iteration count times the number of bytes required by 298 the format if the byte count is not specified. 299 .Pp 300 The input is manipulated in 301 .Dq blocks , 302 where a block is defined as the 303 largest amount of data specified by any format string. 304 Format strings interpreting less than an input block's worth of data, 305 whose last format unit both interprets some number of bytes and does 306 not have a specified iteration count, have the iteration count 307 incremented until the entire input block has been processed or there 308 is not enough data remaining in the block to satisfy the format string. 309 .Pp 310 If, either as a result of user specification or hexdump modifying 311 the iteration count as described above, an iteration count is 312 greater than one, no trailing whitespace characters are output 313 during the last iteration. 314 .Pp 315 It is an error to specify a byte count as well as multiple conversion 316 characters or strings unless all but one of the conversion characters 317 or strings is 318 .Cm \&_a 319 or 320 .Cm \&_A . 321 .Pp 322 If, as a result of the specification of the 323 .Fl n 324 option or end-of-file being reached, input data only partially 325 satisfies a format string, the input block is zero-padded sufficiently 326 to display all available data (i.e., any format units overlapping the 327 end of data will display some number of the zero bytes). 328 .Pp 329 Further output by such format strings is replaced by an equivalent 330 number of spaces. 331 An equivalent number of spaces is defined as the number of spaces 332 output by an 333 .Cm s 334 conversion character with the same field width 335 and precision as the original conversion character or conversion 336 string but with any 337 .Ql + , 338 .Ql \&\ \& , 339 .Ql # 340 conversion flag characters 341 removed, and referencing a NULL string. 342 .Pp 343 If no format strings are specified, the default display is equivalent 344 to specifying the 345 .Fl x 346 option. 347 .Sh EXIT STATUS 348 .Ex -std hexdump 349 .Sh EXAMPLES 350 Display characters using a fieldwidth of 4, 351 and using special names for control characters: 352 .Pp 353 .Dl $ hexdump -e '"%4_u"' file 354 .Pp 355 An example file for use with the 356 .Fl f 357 option, to display the input in perusal format: 358 .Bd -literal -offset indent 359 "%06.6_ao " 12/1 "%3_u " 360 "\et\et" "%_p " 361 "\en" 362 .Ed 363 .Pp 364 An example file for use with the 365 .Fl f 366 option, which implements the equivalent of the 367 .Fl x 368 option: 369 .Bd -literal -offset indent 370 "%07.7_Ax\en" 371 "%07.7_ax " 8/2 " %04x " "\en" 372 .Ed 373 .Sh SEE ALSO 374 .Xr od 1