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. No maxmimum 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 hexdump. This option treats byte groups
58 as words in little-endian byte order. The default grouping of 4
59 bytes may be changed using -g. This option only applies to hex‐
60 dump, leaving the ASCII (or EBCDIC) representation unchanged.
61 The command line switches -r, -p, -i do not work with this mode.
62 -g bytes | -groupsize bytes
64 Separate the output of every <bytes> bytes (two hex characters
65 or eight bit-digits each) by a whitespace. Specify -g 0 to sup‐
66 press grouping. <Bytes> defaults to 2 in normal mode, 4 in lit‐
67 tle-endian mode and 1 in bits mode. Grouping does not apply to
68 postscript or include style.
69 -h | -help
71 Print a summary of available commands and exit. No hex dumping
72 is performed.
73 -i | -include
75 Output in C include file style. A complete static array defini‐
76 tion is written (named after the input file), unless xxd reads
77 from stdin.
78 -l len | -len len
80 Stop after writing <len> octets.
81 -n name | -name name
83 Override the variable name output when -i is used. The array is
84 named name and the length is named name_len.
85 -o offset
87 Add <offset> to the displayed file position.
88 -p | -ps | -postscript | -plain
90 Output in postscript continuous hexdump style. Also known as
91 plain hexdump style.
92 -r | -revert
94 Reverse operation: convert (or patch) hexdump into binary. If
95 not writing to stdout, xxd writes into its output file without
96 truncating it. Use the combination -r -p to read plain hexadeci‐
97 mal dumps without line number information and without a particu‐
98 lar column layout. Additional Whitespace and line-breaks are al‐
99 lowed anywhere.
100 -seek offset
102 When used after -r: revert with <offset> added to file positions
103 found in hexdump.
104 -s [+][-]seek
106 Start at <seek> bytes abs. (or rel.) infile offset. + indicates
107 that the seek is relative to the current stdin file position
108 (meaningless when not reading from stdin). - indicates that the
109 seek should be that many characters from the end of the input
110 (or if combined with +: before the current stdin file position).
111 Without -s option, xxd starts at the current file position.
112 -u Use upper case hex letters. Default is lower case.
114 -v | -version
116 Show version string.
117
119 xxd -r has some builtin magic while evaluating line number information.
120 If the output file is seekable, then the linenumbers at the start of
121 each hexdump line may be out of order, lines may be missing, or over‐
122 lapping. In these cases xxd will lseek(2) to the next position. If the
123 output file is not seekable, only gaps are allowed, which will be
124 filled by null-bytes.
125 xxd -r never generates parse errors. Garbage is silently skipped.
127 When editing hexdumps, please note that xxd -r skips everything on the
129 input line after reading enough columns of hexadecimal data (see option
130 -c). This also means, that changes to the printable ascii (or ebcdic)
131 columns are always ignored. Reverting a plain (or postscript) style
132 hexdump with xxd -r -p does not depend on the correct number of col‐
133 umns. Here anything that looks like a pair of hex-digits is inter‐
134 preted.
135 Note the difference between
137 % xxd -i file
138 and
139 % xxd -i < file
140 xxd -s +seek may be different from xxd -s seek, as lseek(2) is used to
142 "rewind" input. A '+' makes a difference if the input source is stdin,
143 and if stdin's file position is not at the start of the file by the
144 time xxd is started and given its input. The following examples may
145 help to clarify (or further confuse!)...
146 Rewind stdin before reading; needed because the `cat' has already read
148 to the end of stdin.
149 % sh -c "cat > plain_copy; xxd -s 0 > hex_copy" < file
150 Hexdump from file position 0x480 (=1024+128) onwards. The `+' sign
152 means "relative to the current position", thus the `128' adds to the 1k
153 where dd left off.
154 % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +128 > hex_snippet"
155 < file
156 Hexdump from file position 0x100 ( = 1024-768) on.
158 % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +-768 > hex_snippet"
159 < file
160 However, this is a rare situation and the use of `+' is rarely needed.
162 The author prefers to monitor the effect of xxd with strace(1) or
163 truss(1), whenever -s is used.
164
166 Print everything but the first three lines (hex 0x30 bytes) of file.
167 % xxd -s 0x30 file
168 Print 3 lines (hex 0x30 bytes) from the end of file.
170 % xxd -s -0x30 file
171 Print 120 bytes as continuous hexdump with 20 octets per line.
173 % xxd -l 120 -ps -c 20 xxd.1
174 2e54482058584420312022417567757374203139
175 39362220224d616e75616c207061676520666f72
176 20787864220a2e5c220a2e5c222032317374204d
177 617920313939360a2e5c22204d616e2070616765
178 20617574686f723a0a2e5c2220202020546f6e79
179 204e7567656e74203c746f6e79407363746e7567
180 Hexdump the first 120 bytes of this man page with 12 octets per line.
182 % xxd -l 120 -c 12 xxd.1
183 0000000: 2e54 4820 5858 4420 3120 2241 .TH XXD 1 "A
184 000000c: 7567 7573 7420 3139 3936 2220 ugust 1996"
185 0000018: 224d 616e 7561 6c20 7061 6765 "Manual page
186 0000024: 2066 6f72 2078 7864 220a 2e5c for xxd"..\
187 0000030: 220a 2e5c 2220 3231 7374 204d "..\" 21st M
188 000003c: 6179 2031 3939 360a 2e5c 2220 ay 1996..\"
189 0000048: 4d61 6e20 7061 6765 2061 7574 Man page aut
190 0000054: 686f 723a 0a2e 5c22 2020 2020 hor:..\"
191 0000060: 546f 6e79 204e 7567 656e 7420 Tony Nugent
192 000006c: 3c74 6f6e 7940 7363 746e 7567 <tony@sctnug
193 Display just the date from the file xxd.1
195 % xxd -s 0x36 -l 13 -c 13 xxd.1
196 0000036: 3231 7374 204d 6179 2031 3939 36 21st May 1996
197 Copy input_file to output_file and prepend 100 bytes of value 0x00.
199 % xxd input_file | xxd -r -s 100 > output_file
200 Patch the date in the file xxd.1
202 % echo "0000037: 3574 68" | xxd -r - xxd.1
203 % xxd -s 0x36 -l 13 -c 13 xxd.1
204 0000036: 3235 7468 204d 6179 2031 3939 36 25th May 1996
205 Create a 65537 byte file with all bytes 0x00, except for the last one
207 which is 'A' (hex 0x41).
208 % echo "010000: 41" | xxd -r > file
209 Hexdump this file with autoskip.
211 % xxd -a -c 12 file
212 0000000: 0000 0000 0000 0000 0000 0000 ............
213 *
214 000fffc: 0000 0000 40 ....A
215 Create a 1 byte file containing a single 'A' character. The number af‐
217 ter '-r -s' adds to the linenumbers found in the file; in effect, the
218 leading bytes are suppressed.
219 % echo "010000: 41" | xxd -r -s -0x10000 > file
220 Use xxd as a filter within an editor such as vim(1) to hexdump a region
222 marked between `a' and `z'.
223 :'a,'z!xxd
224 Use xxd as a filter within an editor such as vim(1) to recover a binary
226 hexdump marked between `a' and `z'.
227 :'a,'z!xxd -r
228 Use xxd as a filter within an editor such as vim(1) to recover one line
230 of a hexdump. Move the cursor over the line and type:
231 !!xxd -r
232 Read single characters from a serial line
234 % xxd -c1 < /dev/term/b &
235 % stty < /dev/term/b -echo -opost -isig -icanon min 1
236 % echo -n foo > /dev/term/b
237
239 The following error values are returned:
240 0 no errors encountered.
242 -1 operation not supported ( xxd -r -i still impossible).
244 1 error while parsing options.
246 2 problems with input file.
248 3 problems with output file.
250 4,5 desired seek position is unreachable.
252
254 uuencode(1), uudecode(1), patch(1)
255
257 The tools weirdness matches its creators brain. Use entirely at your
258 own risk. Copy files. Trace it. Become a wizard.
259
261 This manual page documents xxd version 1.7
262
264 (c) 1990-1997 by Juergen Weigert
265 <jnweiger@informatik.uni-erlangen.de>
266 Distribute freely and credit me,
268 make money and share with me,
269 lose money and don't ask me.
270 Manual page started by Tony Nugent
272 <tony@sctnugen.ppp.gu.edu.au> <T.Nugent@sct.gu.edu.au>
273 Small changes by Bram Moolenaar. Edited by Juergen Weigert.
274Manual page for xxd August 1996 XXD(1)