1XXD(1) General Commands Manual XXD(1)
2
6 xxd - make a hex dump 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 hex dump. 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 -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. No maximum for -ps. With -ps, 0 results in one
46 long line of output.
47 -C | -capitalize
49 Capitalize variable names in C include file style, when using
50 -i.
51 -E | -EBCDIC
53 Change the character encoding in the righthand column from ASCII
54 to EBCDIC. This does not change the hexadecimal representation.
55 The option is meaningless in combinations with -r, -p or -i.
56 -e Switch to little-endian hex dump. This option treats byte
58 groups as words in little-endian byte order. The default group‐
59 ing of 4 bytes may be changed using -g. This option only ap‐
60 plies to the hex dump, leaving the ASCII (or EBCDIC) representa‐
61 tion unchanged. The command line switches -r, -p, -i do not
62 work with this mode.
63 -g bytes | -groupsize bytes
65 Separate the output of every <bytes> bytes (two hex characters
66 or eight bit digits each) by a whitespace. Specify -g 0 to sup‐
67 press grouping. <Bytes> defaults to 2 in normal mode, 4 in lit‐
68 tle-endian mode and 1 in bits mode. Grouping does not apply to
69 PostScript or include style.
70 -h | -help
72 Print a summary of available commands and exit. No hex dumping
73 is performed.
74 -i | -include
76 Output in C include file style. A complete static array defini‐
77 tion is written (named after the input file), unless xxd reads
78 from stdin.
79 -l len | -len len
81 Stop after writing <len> octets.
82 -n name | -name name
84 Override the variable name output when -i is used. The array is
85 named name and the length is named name_len.
86 -o offset
88 Add <offset> to the displayed file position.
89 -p | -ps | -postscript | -plain
91 Output in PostScript continuous hex dump style. Also known as
92 plain hex dump style.
93 -r | -revert
95 Reverse operation: convert (or patch) hex dump into binary. If
96 not writing to stdout, xxd writes into its output file without
97 truncating it. Use the combination -r -p to read plain hexadeci‐
98 mal dumps without line number information and without a particu‐
99 lar column layout. Additional whitespace and line breaks are al‐
100 lowed anywhere. Use the combination -r -b to read a bits dump
101 instead of a hex dump.
102 -R when
104 In output the hex-value and the value are both colored with the
105 same color depending on the hex-value. Mostly helping to differ‐
106 entiate printable and non-printable characters. when is never,
107 always, or auto. When the $NO_COLOR environment variable is
108 set, colorization will be disabled.
109 -seek offset
111 When used after -r: revert with <offset> added to file positions
112 found in hex dump.
113 -s [+][-]seek
115 Start at <seek> bytes abs. (or rel.) infile offset. + indicates
116 that the seek is relative to the current stdin file position
117 (meaningless when not reading from stdin). - indicates that the
118 seek should be that many characters from the end of the input
119 (or if combined with +: before the current stdin file position).
120 Without -s option, xxd starts at the current file position.
121 -u Use upper-case hex letters. Default is lower-case.
123 -v | -version
125 Show version string.
126
128 xxd -r has some built-in magic while evaluating line number informa‐
129 tion. If the output file is seekable, then the line numbers at the
130 start of each hex dump line may be out of order, lines may be missing,
131 or overlapping. In these cases xxd will lseek(2) to the next position.
132 If the output file is not seekable, only gaps are allowed, which will
133 be filled by null-bytes.
134 xxd -r never generates parse errors. Garbage is silently skipped.
136 When editing hex dumps, please note that xxd -r skips everything on the
138 input line after reading enough columns of hexadecimal data (see option
139 -c). This also means that changes to the printable ASCII (or EBCDIC)
140 columns are always ignored. Reverting a plain (or PostScript) style hex
141 dump with xxd -r -p does not depend on the correct number of columns.
142 Here, anything that looks like a pair of hex digits is interpreted.
143 Note the difference between
145 % xxd -i file
146 and
147 % xxd -i < file
148 xxd -s +seek may be different from xxd -s seek, as lseek(2) is used to
150 "rewind" input. A '+' makes a difference if the input source is stdin,
151 and if stdin's file position is not at the start of the file by the
152 time xxd is started and given its input. The following examples may
153 help to clarify (or further confuse!):
154 Rewind stdin before reading; needed because the `cat' has already read
156 to the end of stdin.
157 % sh -c "cat > plain_copy; xxd -s 0 > hex_copy" < file
158 Hex dump from file position 0x480 (=1024+128) onwards. The `+' sign
160 means "relative to the current position", thus the `128' adds to the 1k
161 where dd left off.
162 % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +128 > hex_snippet"
163 < file
164 Hex dump from file position 0x100 (=1024-768) onwards.
166 % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +-768 > hex_snippet"
167 < file
168 However, this is a rare situation and the use of `+' is rarely needed.
170 The author prefers to monitor the effect of xxd with strace(1) or
171 truss(1), whenever -s is used.
172
174 Print everything but the first three lines (hex 0x30 bytes) of file.
175 % xxd -s 0x30 file
176 Print 3 lines (hex 0x30 bytes) from the end of file.
178 % xxd -s -0x30 file
179 Print 120 bytes as a continuous hex dump with 20 octets per line.
181 % xxd -l 120 -ps -c 20 xxd.1
182 2e54482058584420312022417567757374203139
183 39362220224d616e75616c207061676520666f72
184 20787864220a2e5c220a2e5c222032317374204d
185 617920313939360a2e5c22204d616e2070616765
186 20617574686f723a0a2e5c2220202020546f6e79
187 204e7567656e74203c746f6e79407363746e7567
188 Hex dump the first 120 bytes of this man page with 12 octets per line.
190 % xxd -l 120 -c 12 xxd.1
191 0000000: 2e54 4820 5858 4420 3120 2241 .TH XXD 1 "A
192 000000c: 7567 7573 7420 3139 3936 2220 ugust 1996"
193 0000018: 224d 616e 7561 6c20 7061 6765 "Manual page
194 0000024: 2066 6f72 2078 7864 220a 2e5c for xxd"..\
195 0000030: 220a 2e5c 2220 3231 7374 204d "..\" 21st M
196 000003c: 6179 2031 3939 360a 2e5c 2220 ay 1996..\"
197 0000048: 4d61 6e20 7061 6765 2061 7574 Man page aut
198 0000054: 686f 723a 0a2e 5c22 2020 2020 hor:..\"
199 0000060: 546f 6e79 204e 7567 656e 7420 Tony Nugent
200 000006c: 3c74 6f6e 7940 7363 746e 7567 <tony@sctnug
201 Display just the date from the file xxd.1
203 % xxd -s 0x36 -l 13 -c 13 xxd.1
204 0000036: 3231 7374 204d 6179 2031 3939 36 21st May 1996
205 Copy input_file to output_file and prepend 100 bytes of value 0x00.
207 % xxd input_file | xxd -r -s 100 > output_file
208 Patch the date in the file xxd.1
210 % echo "0000037: 3574 68" | xxd -r - xxd.1
211 % xxd -s 0x36 -l 13 -c 13 xxd.1
212 0000036: 3235 7468 204d 6179 2031 3939 36 25th May 1996
213 Create a 65537 byte file with all bytes 0x00, except for the last one
215 which is 'A' (hex 0x41).
216 % echo "010000: 41" | xxd -r > file
217 Hex dump this file with autoskip.
219 % xxd -a -c 12 file
220 0000000: 0000 0000 0000 0000 0000 0000 ............
221 *
222 000fffc: 0000 0000 40 ....A
223 Create a 1 byte file containing a single 'A' character. The number af‐
225 ter '-r -s' adds to the line numbers found in the file; in effect, the
226 leading bytes are suppressed.
227 % echo "010000: 41" | xxd -r -s -0x10000 > file
228 Use xxd as a filter within an editor such as vim(1) to hex dump a re‐
230 gion marked between `a' and `z'.
231 :'a,'z!xxd
232 Use xxd as a filter within an editor such as vim(1) to recover a binary
234 hex dump marked between `a' and `z'.
235 :'a,'z!xxd -r
236 Use xxd as a filter within an editor such as vim(1) to recover one line
238 of a hex dump. Move the cursor over the line and type:
239 !!xxd -r
240 Read single characters from a serial line
242 % xxd -c1 < /dev/term/b &
243 % stty < /dev/term/b -echo -opost -isig -icanon min 1
244 % echo -n foo > /dev/term/b
245
247 The following error values are returned:
248 0 no errors encountered.
250 -1 operation not supported (xxd -r -i still impossible).
252 1 error while parsing options.
254 2 problems with input file.
256 3 problems with output file.
258 4,5 desired seek position is unreachable.
260
262 uuencode(1), uudecode(1), patch(1)
263
265 The tool's weirdness matches its creator's brain. Use entirely at your
266 own risk. Copy files. Trace it. Become a wizard.
267
269 This manual page documents xxd version 1.7
270
272 (c) 1990-1997 by Juergen Weigert
273 <jnweiger@informatik.uni-erlangen.de>
274 Distribute freely and credit me,
276 make money and share with me,
277 lose money and don't ask me.
278 Manual page started by Tony Nugent
280 <tony@sctnugen.ppp.gu.edu.au> <T.Nugent@sct.gu.edu.au>
281 Small changes by Bram Moolenaar. Edited by Juergen Weigert.
282Manual page for xxd August 1996 XXD(1)