1XXD(1) General Commands Manual XXD(1)
2
6 xxd - make a hexdump or do the reverse.
7
9 xxd -h[elp]
10 xxd [options] [infile [outfile]]
11 xxd -r[evert] [options] [infile [outfile]]
12
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
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 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 -a | -autoskip
33 Toggle autoskip: A single '*' replaces nul-lines. Default off.
34 -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 -c cols | -cols cols
44 Format <cols> octets per line. Default 16 (-i: 12, -ps: 30, -b:
45 6). Max 256.
46 -C | -capitalize
48 Capitalize variable names in C include file style, when using
49 -i.
50 -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 -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 -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 -h | -help
70 Print a summary of available commands and exit. No hex dumping
71 is performed.
72 -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 -l len | -len len
79 Stop after writing <len> octets.
80 -o offset
82 Add <offset> to the displayed file position.
83 -p | -ps | -postscript | -plain
85 Output in postscript continuous hexdump style. Also known as
86 plain hexdump style.
87 -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 -seek offset
97 When used after -r: revert with <offset> added to file positions
98 found in hexdump.
99 -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 -u Use upper case hex letters. Default is lower case.
109 -v | -version
111 Show version string.
112
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 xxd -r never generates parse errors. Garbage is silently skipped.
122 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 Note the difference between
132 % xxd -i file
133 and
134 % xxd -i < file
135 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 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 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 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 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
161 Print everything but the first three lines (hex 0x30 bytes) of file.
162 % xxd -s 0x30 file
163 Print 3 lines (hex 0x30 bytes) from the end of file.
165 % xxd -s -0x30 file
166 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 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 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 Copy input_file to output_file and prepend 100 bytes of value 0x00.
194 % xxd input_file | xxd -r -s 100 > output_file
195 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 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 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 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 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 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 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 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
234 The following error values are returned:
235 0 no errors encountered.
237 -1 operation not supported ( xxd -r -i still impossible).
239 1 error while parsing options.
241 2 problems with input file.
243 3 problems with output file.
245 4,5 desired seek position is unreachable.
247
249 uuencode(1), uudecode(1), patch(1)
250
252 The tools weirdness matches its creators brain. Use entirely at your
253 own risk. Copy files. Trace it. Become a wizard.
254
256 This manual page documents xxd version 1.7
257
259 (c) 1990-1997 by Juergen Weigert
260 <jnweiger@informatik.uni-erlangen.de>
261 Distribute freely and credit me,
263 make money and share with me,
264 lose money and don't ask me.
265 Manual page started by Tony Nugent
267 <tony@sctnugen.ppp.gu.edu.au> <T.Nugent@sct.gu.edu.au>
268 Small changes by Bram Moolenaar. Edited by Juergen Weigert.
269Manual page for xxd August 1996 XXD(1)