1XXD(1) General Commands Manual XXD(1) 2 3 4 5NAME 6 xxd - make a hexdump or do the reverse. 7 8SYNOPSIS 9 xxd -h[elp] 10 xxd [options] [infile [outfile]] 11 xxd -r[evert] [options] [infile [outfile]] 12 13DESCRIPTION 14 xxd creates a hex dump of a given file or standard input. It can also 15 convert a hex dump back to its original binary form. Like uuencode(1) 16 and uudecode(1) it allows the transmission of binary data in a `mail- 17 safe' ASCII representation, but has the advantage of decoding to stan‐ 18 dard output. Moreover, it can be used to perform binary file patching. 19 20OPTIONS 21 If no infile is given, standard input is read. If infile is specified 22 as a `-' character, then input is taken from standard input. If no 23 outfile is given (or a `-' character is in its place), results are sent 24 to standard output. 25 26 Note that a "lazy" parser is used which does not check for more than 27 the first option letter, unless the option is followed by a parameter. 28 Spaces between a single option letter and its parameter are optional. 29 Parameters to options can be specified in decimal, hexadecimal or octal 30 notation. Thus -c8, -c 8, -c 010 and -cols 8 are all equivalent. 31 32 -a | -autoskip 33 Toggle autoskip: A single '*' replaces nul-lines. Default off. 34 35 -b | -bits 36 Switch to bits (binary digits) dump, rather than hexdump. This 37 option writes octets as eight digits "1"s and "0"s instead of a 38 normal hexadecimal dump. Each line is preceded by a line number 39 in hexadecimal and followed by an ascii (or ebcdic) representa‐ 40 tion. The command line switches -r, -p, -i do not work with this 41 mode. 42 43 -c cols | -cols cols 44 Format <cols> octets per line. Default 16 (-i: 12, -ps: 30, -b: 45 6). Max 256. 46 47 -C | -capitalize 48 Capitalize variable names in C include file style, when using 49 -i. 50 51 -E | -EBCDIC 52 Change the character encoding in the righthand column from ASCII 53 to EBCDIC. This does not change the hexadecimal representation. 54 The option is meaningless in combinations with -r, -p or -i. 55 56 -e Switch to little-endian hexdump. This option treats byte groups 57 as words in little-endian byte order. The default grouping of 4 58 bytes may be changed using -g. This option only applies to hex‐ 59 dump, leaving the ASCII (or EBCDIC) representation unchanged. 60 The command line switches -r, -p, -i do not work with this mode. 61 62 -g bytes | -groupsize bytes 63 Separate the output of every <bytes> bytes (two hex characters 64 or eight bit-digits each) by a whitespace. Specify -g 0 to sup‐ 65 press grouping. <Bytes> defaults to 2 in normal mode, 4 in lit‐ 66 tle-endian mode and 1 in bits mode. Grouping does not apply to 67 postscript or include style. 68 69 -h | -help 70 Print a summary of available commands and exit. No hex dumping 71 is performed. 72 73 -i | -include 74 Output in C include file style. A complete static array defini‐ 75 tion is written (named after the input file), unless xxd reads 76 from stdin. 77 78 -l len | -len len 79 Stop after writing <len> octets. 80 81 -o offset 82 Add <offset> to the displayed file position. 83 84 -p | -ps | -postscript | -plain 85 Output in postscript continuous hexdump style. Also known as 86 plain hexdump style. 87 88 -r | -revert 89 Reverse operation: convert (or patch) hexdump into binary. If 90 not writing to stdout, xxd writes into its output file without 91 truncating it. Use the combination -r -p to read plain hexadeci‐ 92 mal dumps without line number information and without a particu‐ 93 lar column layout. Additional Whitespace and line-breaks are 94 allowed anywhere. 95 96 -seek offset 97 When used after -r: revert with <offset> added to file positions 98 found in hexdump. 99 100 -s [+][-]seek 101 Start at <seek> bytes abs. (or rel.) infile offset. + indicates 102 that the seek is relative to the current stdin file position 103 (meaningless when not reading from stdin). - indicates that the 104 seek should be that many characters from the end of the input 105 (or if combined with +: before the current stdin file position). 106 Without -s option, xxd starts at the current file position. 107 108 -u Use upper case hex letters. Default is lower case. 109 110 -v | -version 111 Show version string. 112 113CAVEATS 114 xxd -r has some builtin magic while evaluating line number information. 115 If the output file is seekable, then the linenumbers at the start of 116 each hexdump line may be out of order, lines may be missing, or over‐ 117 lapping. In these cases xxd will lseek(2) to the next position. If the 118 output file is not seekable, only gaps are allowed, which will be 119 filled by null-bytes. 120 121 xxd -r never generates parse errors. Garbage is silently skipped. 122 123 When editing hexdumps, please note that xxd -r skips everything on the 124 input line after reading enough columns of hexadecimal data (see option 125 -c). This also means, that changes to the printable ascii (or ebcdic) 126 columns are always ignored. Reverting a plain (or postscript) style 127 hexdump with xxd -r -p does not depend on the correct number of col‐ 128 umns. Here anything that looks like a pair of hex-digits is inter‐ 129 preted. 130 131 Note the difference between 132 % xxd -i file 133 and 134 % xxd -i < file 135 136 xxd -s +seek may be different from xxd -s seek, as lseek(2) is used to 137 "rewind" input. A '+' makes a difference if the input source is stdin, 138 and if stdin's file position is not at the start of the file by the 139 time xxd is started and given its input. The following examples may 140 help to clarify (or further confuse!)... 141 142 Rewind stdin before reading; needed because the `cat' has already read 143 to the end of stdin. 144 % sh -c "cat > plain_copy; xxd -s 0 > hex_copy" < file 145 146 Hexdump from file position 0x480 (=1024+128) onwards. The `+' sign 147 means "relative to the current position", thus the `128' adds to the 1k 148 where dd left off. 149 % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +128 > hex_snippet" 150 < file 151 152 Hexdump from file position 0x100 ( = 1024-768) on. 153 % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +-768 > hex_snippet" 154 < file 155 156 However, this is a rare situation and the use of `+' is rarely needed. 157 The author prefers to monitor the effect of xxd with strace(1) or 158 truss(1), whenever -s is used. 159 160EXAMPLES 161 Print everything but the first three lines (hex 0x30 bytes) of file. 162 % xxd -s 0x30 file 163 164 Print 3 lines (hex 0x30 bytes) from the end of file. 165 % xxd -s -0x30 file 166 167 Print 120 bytes as continuous hexdump with 20 octets per line. 168 % xxd -l 120 -ps -c 20 xxd.1 169 2e54482058584420312022417567757374203139 170 39362220224d616e75616c207061676520666f72 171 20787864220a2e5c220a2e5c222032317374204d 172 617920313939360a2e5c22204d616e2070616765 173 20617574686f723a0a2e5c2220202020546f6e79 174 204e7567656e74203c746f6e79407363746e7567 175 176 Hexdump the first 120 bytes of this man page with 12 octets per line. 177 % xxd -l 120 -c 12 xxd.1 178 0000000: 2e54 4820 5858 4420 3120 2241 .TH XXD 1 "A 179 000000c: 7567 7573 7420 3139 3936 2220 ugust 1996" 180 0000018: 224d 616e 7561 6c20 7061 6765 "Manual page 181 0000024: 2066 6f72 2078 7864 220a 2e5c for xxd"..\ 182 0000030: 220a 2e5c 2220 3231 7374 204d "..\" 21st M 183 000003c: 6179 2031 3939 360a 2e5c 2220 ay 1996..\" 184 0000048: 4d61 6e20 7061 6765 2061 7574 Man page aut 185 0000054: 686f 723a 0a2e 5c22 2020 2020 hor:..\" 186 0000060: 546f 6e79 204e 7567 656e 7420 Tony Nugent 187 000006c: 3c74 6f6e 7940 7363 746e 7567 <tony@sctnug 188 189 Display just the date from the file xxd.1 190 % xxd -s 0x36 -l 13 -c 13 xxd.1 191 0000036: 3231 7374 204d 6179 2031 3939 36 21st May 1996 192 193 Copy input_file to output_file and prepend 100 bytes of value 0x00. 194 % xxd input_file | xxd -r -s 100 > output_file 195 196 Patch the date in the file xxd.1 197 % echo "0000037: 3574 68" | xxd -r - xxd.1 198 % xxd -s 0x36 -l 13 -c 13 xxd.1 199 0000036: 3235 7468 204d 6179 2031 3939 36 25th May 1996 200 201 Create a 65537 byte file with all bytes 0x00, except for the last one 202 which is 'A' (hex 0x41). 203 % echo "010000: 41" | xxd -r > file 204 205 Hexdump this file with autoskip. 206 % xxd -a -c 12 file 207 0000000: 0000 0000 0000 0000 0000 0000 ............ 208 * 209 000fffc: 0000 0000 40 ....A 210 211 Create a 1 byte file containing a single 'A' character. The number 212 after '-r -s' adds to the linenumbers found in the file; in effect, the 213 leading bytes are suppressed. 214 % echo "010000: 41" | xxd -r -s -0x10000 > file 215 216 Use xxd as a filter within an editor such as vim(1) to hexdump a region 217 marked between `a' and `z'. 218 :'a,'z!xxd 219 220 Use xxd as a filter within an editor such as vim(1) to recover a binary 221 hexdump marked between `a' and `z'. 222 :'a,'z!xxd -r 223 224 Use xxd as a filter within an editor such as vim(1) to recover one line 225 of a hexdump. Move the cursor over the line and type: 226 !!xxd -r 227 228 Read single characters from a serial line 229 % xxd -c1 < /dev/term/b & 230 % stty < /dev/term/b -echo -opost -isig -icanon min 1 231 % echo -n foo > /dev/term/b 232 233RETURN VALUES 234 The following error values are returned: 235 236 0 no errors encountered. 237 238 -1 operation not supported ( xxd -r -i still impossible). 239 240 1 error while parsing options. 241 242 2 problems with input file. 243 244 3 problems with output file. 245 246 4,5 desired seek position is unreachable. 247 248SEE ALSO 249 uuencode(1), uudecode(1), patch(1) 250 251WARNINGS 252 The tools weirdness matches its creators brain. Use entirely at your 253 own risk. Copy files. Trace it. Become a wizard. 254 255VERSION 256 This manual page documents xxd version 1.7 257 258AUTHOR 259 (c) 1990-1997 by Juergen Weigert 260 <[email protected]> 261 262 Distribute freely and credit me, 263 make money and share with me, 264 lose money and don't ask me. 265 266 Manual page started by Tony Nugent 267 <[email protected]> <[email protected]> 268 Small changes by Bram Moolenaar. Edited by Juergen Weigert. 269 270Manual page for xxd August 1996 XXD(1) 271