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 -E | -EBCDIC
48 Change the character encoding in the righthand column from ASCII
49 to EBCDIC. This does not change the hexadecimal representation.
50 The option is meaningless in combinations with -r, -p or -i.
51 -g bytes | -groupsize bytes
53 separate the output of every <bytes> bytes (two hex characters
54 or eight bit-digits each) by a whitespace. Specify -g 0 to sup‐
55 press grouping. <Bytes> defaults to 2 in normal mode and 1 in
56 bits mode. Grouping does not apply to postscript or include
57 style.
58 -h | -help
60 print a summary of available commands and exit. No hex dumping
61 is performed.
62 -i | -include
64 output in C include file style. A complete static array defini‐
65 tion is written (named after the input file), unless xxd reads
66 from stdin.
67 -l len | -len len
69 stop after writing <len> octets.
70 -p | -ps | -postscript | -plain
72 output in postscript continuous hexdump style. Also known as
73 plain hexdump style.
74 -r | -revert
76 reverse operation: convert (or patch) hexdump into binary. If
77 not writing to stdout, xxd writes into its output file without
78 truncating it. Use the combination -r -p to read plain hexadeci‐
79 mal dumps without line number information and without a particu‐
80 lar column layout. Additional Whitespace and line-breaks are
81 allowed anywhere.
82 -seek offset
84 When used after -r: revert with <offset> added to file positions
85 found in hexdump.
86 -s [+][-]seek
88 start at <seek> bytes abs. (or rel.) infile offset. + indicates
89 that the seek is relative to the current stdin file position
90 (meaningless when not reading from stdin). - indicates that the
91 seek should be that many characters from the end of the input
92 (or if combined with +: before the current stdin file position).
93 Without -s option, xxd starts at the current file position.
94 -u use upper case hex letters. Default is lower case.
96 -v | -version
98 show version string.
99
101 xxd -r has some builtin magic while evaluating line number information.
102 If the output file is seekable, then the linenumbers at the start of
103 each hexdump line may be out of order, lines may be missing, or over‐
104 lapping. In these cases xxd will lseek(2) to the next position. If the
105 output file is not seekable, only gaps are allowed, which will be
106 filled by null-bytes.
107 xxd -r never generates parse errors. Garbage is silently skipped.
109 When editing hexdumps, please note that xxd -r skips everything on the
111 input line after reading enough columns of hexadecimal data (see option
112 -c). This also means, that changes to the printable ascii (or ebcdic)
113 columns are always ignored. Reverting a plain (or postscript) style
114 hexdump with xxd -r -p does not depend on the correct number of col‐
115 umns. Here anything that looks like a pair of hex-digits is inter‐
116 preted.
117 Note the difference between
119 % xxd -i file
120 and
121 % xxd -i < file
122 xxd -s +seek may be different from xxd -s seek, as lseek(2) is used to
124 "rewind" input. A '+' makes a difference if the input source is stdin,
125 and if stdin's file position is not at the start of the file by the
126 time xxd is started and given its input. The following examples may
127 help to clarify (or further confuse!)...
128 Rewind stdin before reading; needed because the `cat' has already read
130 to the end of stdin.
131 % sh -c "cat > plain_copy; xxd -s 0 > hex_copy" < file
132 Hexdump from file position 0x480 (=1024+128) onwards. The `+' sign
134 means "relative to the current position", thus the `128' adds to the 1k
135 where dd left off.
136 % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +128 > hex_snippet"
137 < file
138 Hexdump from file position 0x100 ( = 1024-768) on.
140 % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +-768 > hex_snippet"
141 < file
142 However, this is a rare situation and the use of `+' is rarely needed.
144 The author prefers to monitor the effect of xxd with strace(1) or
145 truss(1), whenever -s is used.
146
148 Print everything but the first three lines (hex 0x30 bytes) of file.
149 % xxd -s 0x30 file
150 Print 3 lines (hex 0x30 bytes) from the end of file.
152 % xxd -s -0x30 file
153 Print 120 bytes as continuous hexdump with 20 octets per line.
155 % xxd -l 120 -ps -c 20 xxd.1
156 2e54482058584420312022417567757374203139
157 39362220224d616e75616c207061676520666f72
158 20787864220a2e5c220a2e5c222032317374204d
159 617920313939360a2e5c22204d616e2070616765
160 20617574686f723a0a2e5c2220202020546f6e79
161 204e7567656e74203c746f6e79407363746e7567
162 Hexdump the first 120 bytes of this man page with 12 octets per line.
164 % xxd -l 120 -c 12 xxd.1
165 0000000: 2e54 4820 5858 4420 3120 2241 .TH XXD 1 "A
166 000000c: 7567 7573 7420 3139 3936 2220 ugust 1996"
167 0000018: 224d 616e 7561 6c20 7061 6765 "Manual page
168 0000024: 2066 6f72 2078 7864 220a 2e5c for xxd"..\
169 0000030: 220a 2e5c 2220 3231 7374 204d "..\" 21st M
170 000003c: 6179 2031 3939 360a 2e5c 2220 ay 1996..\"
171 0000048: 4d61 6e20 7061 6765 2061 7574 Man page aut
172 0000054: 686f 723a 0a2e 5c22 2020 2020 hor:..\"
173 0000060: 546f 6e79 204e 7567 656e 7420 Tony Nugent
174 000006c: 3c74 6f6e 7940 7363 746e 7567 <tony@sctnug
175 Display just the date from the file xxd.1
177 % xxd -s 0x36 -l 13 -c 13 xxd.1
178 0000036: 3231 7374 204d 6179 2031 3939 36 21st May 1996
179 Copy input_file to output_file and prepend 100 bytes of value 0x00.
181 % xxd input_file | xxd -r -s 100 > output_file
182 Patch the date in the file xxd.1
184 % echo "0000037: 3574 68" | xxd -r - xxd.1
185 % xxd -s 0x36 -l 13 -c 13 xxd.1
186 0000036: 3235 7468 204d 6179 2031 3939 36 25th May 1996
187 Create a 65537 byte file with all bytes 0x00, except for the last one
189 which is 'A' (hex 0x41).
190 % echo "010000: 41" | xxd -r > file
191 Hexdump this file with autoskip.
193 % xxd -a -c 12 file
194 0000000: 0000 0000 0000 0000 0000 0000 ............
195 *
196 000fffc: 0000 0000 40 ....A
197 Create a 1 byte file containing a single 'A' character. The number
199 after '-r -s' adds to the linenumbers found in the file; in effect, the
200 leading bytes are suppressed.
201 % echo "010000: 41" | xxd -r -s -0x10000 > file
202 Use xxd as a filter within an editor such as vim(1) to hexdump a region
204 marked between `a' and `z'.
205 :'a,'z!xxd
206 Use xxd as a filter within an editor such as vim(1) to recover a binary
208 hexdump marked between `a' and `z'.
209 :'a,'z!xxd -r
210 Use xxd as a filter within an editor such as vim(1) to recover one line
212 of a hexdump. Move the cursor over the line and type:
213 !!xxd -r
214 Read single characters from a serial line
216 % xxd -c1 < /dev/term/b &
217 % stty < /dev/term/b -echo -opost -isig -icanon min 1
218 % echo -n foo > /dev/term/b
219
221 The following error values are returned:
222 0 no errors encountered.
224 -1 operation not supported ( xxd -r -i still impossible).
226 1 error while parsing options.
228 2 problems with input file.
230 3 problems with output file.
232 4,5 desired seek position is unreachable.
234
236 uuencode(1), uudecode(1), patch(1)
237
239 The tools weirdness matches its creators brain. Use entirely at your
240 own risk. Copy files. Trace it. Become a wizard.
241
243 This manual page documents xxd version 1.7
244
246 (c) 1990-1997 by Juergen Weigert
247 <jnweiger@informatik.uni-erlangen.de>
248 Distribute freely and credit me,
250 make money and share with me,
251 lose money and don't ask me.
252 Manual page started by Tony Nugent
254 <tony@sctnugen.ppp.gu.edu.au> <T.Nugent@sct.gu.edu.au>
255 Small changes by Bram Moolenaar. Edited by Juergen Weigert.
256Manual page for xxd August 1996 XXD(1)