| XXD(1) General Commands Manual XXD(1) |
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| NAME |
| xxd - make a hex dump or do the reverse. |
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| SYNOPSIS |
| xxd -h[elp] |
| xxd [options] [infile [outfile]] |
| xxd -r[evert] [options] [infile [outfile]] |
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| DESCRIPTION |
| xxd creates a hex dump of a given file or standard input. It can also |
| convert a hex dump back to its original binary form. Like uuencode(1) |
| and uudecode(1) it allows the transmission of binary data in a `mail- |
| safe' ASCII representation, but has the advantage of decoding to stan‐ |
| dard output. Moreover, it can be used to perform binary file patching. |
| |
| OPTIONS |
| If no infile is given, standard input is read. If infile is specified |
| as a `-' character, then input is taken from standard input. If no |
| outfile is given (or a `-' character is in its place), results are sent |
| to standard output. |
| |
| Note that a "lazy" parser is used which does not check for more than |
| the first option letter, unless the option is followed by a parameter. |
| Spaces between a single option letter and its parameter are optional. |
| Parameters to options can be specified in decimal, hexadecimal or octal |
| notation. Thus -c8, -c 8, -c 010 and -cols 8 are all equivalent. |
| |
| -a | -autoskip |
| Toggle autoskip: A single '*' replaces NUL-lines. Default off. |
| |
| -b | -bits |
| Switch to bits (binary digits) dump, rather than hex dump. This |
| option writes octets as eight digits "1"s and "0"s instead of a |
| normal hexadecimal dump. Each line is preceded by a line number |
| in hexadecimal and followed by an ASCII (or EBCDIC) representa‐ |
| tion. The command line switches -p, -i do not work with this |
| mode. |
| |
| -c cols | -cols cols |
| Format <cols> octets per line. Default 16 (-i: 12, -ps: 30, -b: |
| 6). Max 256. No maximum for -ps. With -ps, 0 results in one |
| long line of output. |
| |
| -C | -capitalize |
| Capitalize variable names in C include file style, when using |
| -i. |
| |
| -d show offset in decimal instead of hex. |
| |
| -E | -EBCDIC |
| Change the character encoding in the righthand column from ASCII |
| to EBCDIC. This does not change the hexadecimal representation. |
| The option is meaningless in combinations with -r, -p or -i. |
| |
| -e Switch to little-endian hex dump. This option treats byte |
| groups as words in little-endian byte order. The default group‐ |
| ing of 4 bytes may be changed using -g. This option only ap‐ |
| plies to the hex dump, leaving the ASCII (or EBCDIC) representa‐ |
| tion unchanged. The command line switches -r, -p, -i do not |
| work with this mode. |
| |
| -g bytes | -groupsize bytes |
| Separate the output of every <bytes> bytes (two hex characters |
| or eight bit digits each) by a whitespace. Specify -g 0 to sup‐ |
| press grouping. <Bytes> defaults to 2 in normal mode, 4 in lit‐ |
| tle-endian mode and 1 in bits mode. Grouping does not apply to |
| PostScript or include style. |
| |
| -h | -help |
| Print a summary of available commands and exit. No hex dumping |
| is performed. |
| |
| -i | -include |
| Output in C include file style. A complete static array defini‐ |
| tion is written (named after the input file), unless xxd reads |
| from stdin. |
| |
| -l len | -len len |
| Stop after writing <len> octets. |
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| -n name | -name name |
| Override the variable name output when -i is used. The array is |
| named name and the length is named name_len. |
| |
| -o offset |
| Add <offset> to the displayed file position. |
| |
| -p | -ps | -postscript | -plain |
| Output in PostScript continuous hex dump style. Also known as |
| plain hex dump style. |
| |
| -r | -revert |
| Reverse operation: convert (or patch) hex dump into binary. If |
| not writing to stdout, xxd writes into its output file without |
| truncating it. Use the combination -r -p to read plain hexadeci‐ |
| mal dumps without line number information and without a particu‐ |
| lar column layout. Additional whitespace and line breaks are al‐ |
| lowed anywhere. Use the combination -r -b to read a bits dump |
| instead of a hex dump. |
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| -R when |
| In the output the hex-value and the value are both colored with |
| the same color depending on the hex-value. Mostly helping to |
| differentiate printable and non-printable characters. when is |
| never, always, or auto (default: auto). When the $NO_COLOR en‐ |
| vironment variable is set, colorization will be disabled. |
| |
| -seek offset |
| When used after -r: revert with <offset> added to file positions |
| found in hex dump. |
| |
| -s [+][-]seek |
| Start at <seek> bytes abs. (or rel.) infile offset. + indicates |
| that the seek is relative to the current stdin file position |
| (meaningless when not reading from stdin). - indicates that the |
| seek should be that many characters from the end of the input |
| (or if combined with +: before the current stdin file position). |
| Without -s option, xxd starts at the current file position. |
| |
| -u Use upper-case hex letters. Default is lower-case. |
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| -v | -version |
| Show version string. |
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| CAVEATS |
| xxd -r has some built-in magic while evaluating line number informa‐ |
| tion. If the output file is seekable, then the line numbers at the |
| start of each hex dump line may be out of order, lines may be missing, |
| or overlapping. In these cases xxd will lseek(2) to the next position. |
| If the output file is not seekable, only gaps are allowed, which will |
| be filled by null-bytes. |
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| xxd -r never generates parse errors. Garbage is silently skipped. |
| |
| When editing hex dumps, please note that xxd -r skips everything on the |
| input line after reading enough columns of hexadecimal data (see option |
| -c). This also means that changes to the printable ASCII (or EBCDIC) |
| columns are always ignored. Reverting a plain (or PostScript) style hex |
| dump with xxd -r -p does not depend on the correct number of columns. |
| Here, anything that looks like a pair of hex digits is interpreted. |
| |
| Note the difference between |
| % xxd -i file |
| and |
| % xxd -i < file |
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| xxd -s +seek may be different from xxd -s seek, as lseek(2) is used to |
| "rewind" input. A '+' makes a difference if the input source is stdin, |
| and if stdin's file position is not at the start of the file by the |
| time xxd is started and given its input. The following examples may |
| help to clarify (or further confuse!): |
| |
| Rewind stdin before reading; needed because the `cat' has already read |
| to the end of stdin. |
| % sh -c "cat > plain_copy; xxd -s 0 > hex_copy" < file |
| |
| Hex dump from file position 0x480 (=1024+128) onwards. The `+' sign |
| means "relative to the current position", thus the `128' adds to the 1k |
| where dd left off. |
| % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +128 > hex_snippet" |
| < file |
| |
| Hex dump from file position 0x100 (=1024-768) onwards. |
| % sh -c "dd of=plain_snippet bs=1k count=1; xxd -s +-768 > hex_snippet" |
| < file |
| |
| However, this is a rare situation and the use of `+' is rarely needed. |
| The author prefers to monitor the effect of xxd with strace(1) or |
| truss(1), whenever -s is used. |
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| EXAMPLES |
| Print everything but the first three lines (hex 0x30 bytes) of file. |
| % xxd -s 0x30 file |
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| Print 3 lines (hex 0x30 bytes) from the end of file. |
| % xxd -s -0x30 file |
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| Print 120 bytes as a continuous hex dump with 20 octets per line. |
| % xxd -l 120 -ps -c 20 xxd.1 |
| 2e54482058584420312022417567757374203139 |
| 39362220224d616e75616c207061676520666f72 |
| 20787864220a2e5c220a2e5c222032317374204d |
| 617920313939360a2e5c22204d616e2070616765 |
| 20617574686f723a0a2e5c2220202020546f6e79 |
| 204e7567656e74203c746f6e79407363746e7567 |
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| Hex dump the first 120 bytes of this man page with 12 octets per line. |
| % xxd -l 120 -c 12 xxd.1 |
| 0000000: 2e54 4820 5858 4420 3120 2241 .TH XXD 1 "A |
| 000000c: 7567 7573 7420 3139 3936 2220 ugust 1996" |
| 0000018: 224d 616e 7561 6c20 7061 6765 "Manual page |
| 0000024: 2066 6f72 2078 7864 220a 2e5c for xxd"..\ |
| 0000030: 220a 2e5c 2220 3231 7374 204d "..\" 21st M |
| 000003c: 6179 2031 3939 360a 2e5c 2220 ay 1996..\" |
| 0000048: 4d61 6e20 7061 6765 2061 7574 Man page aut |
| 0000054: 686f 723a 0a2e 5c22 2020 2020 hor:..\" |
| 0000060: 546f 6e79 204e 7567 656e 7420 Tony Nugent |
| 000006c: 3c74 6f6e 7940 7363 746e 7567 <tony@sctnug |
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| Display just the date from the file xxd.1 |
| % xxd -s 0x36 -l 13 -c 13 xxd.1 |
| 0000036: 3231 7374 204d 6179 2031 3939 36 21st May 1996 |
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| Copy input_file to output_file and prepend 100 bytes of value 0x00. |
| % xxd input_file | xxd -r -s 100 > output_file |
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| Patch the date in the file xxd.1 |
| % echo "0000037: 3574 68" | xxd -r - xxd.1 |
| % xxd -s 0x36 -l 13 -c 13 xxd.1 |
| 0000036: 3235 7468 204d 6179 2031 3939 36 25th May 1996 |
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| Create a 65537 byte file with all bytes 0x00, except for the last one |
| which is 'A' (hex 0x41). |
| % echo "010000: 41" | xxd -r > file |
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| Hex dump this file with autoskip. |
| % xxd -a -c 12 file |
| 0000000: 0000 0000 0000 0000 0000 0000 ............ |
| * |
| 000fffc: 0000 0000 40 ....A |
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| Create a 1 byte file containing a single 'A' character. The number af‐ |
| ter '-r -s' adds to the line numbers found in the file; in effect, the |
| leading bytes are suppressed. |
| % echo "010000: 41" | xxd -r -s -0x10000 > file |
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| Use xxd as a filter within an editor such as vim(1) to hex dump a re‐ |
| gion marked between `a' and `z'. |
| :'a,'z!xxd |
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| Use xxd as a filter within an editor such as vim(1) to recover a binary |
| hex dump marked between `a' and `z'. |
| :'a,'z!xxd -r |
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| Use xxd as a filter within an editor such as vim(1) to recover one line |
| of a hex dump. Move the cursor over the line and type: |
| !!xxd -r |
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| Read single characters from a serial line |
| % xxd -c1 < /dev/term/b & |
| % stty < /dev/term/b -echo -opost -isig -icanon min 1 |
| % echo -n foo > /dev/term/b |
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| RETURN VALUES |
| The following error values are returned: |
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| 0 no errors encountered. |
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| -1 operation not supported (xxd -r -i still impossible). |
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| 1 error while parsing options. |
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| 2 problems with input file. |
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| 3 problems with output file. |
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| 4,5 desired seek position is unreachable. |
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| SEE ALSO |
| uuencode(1), uudecode(1), patch(1) |
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| WARNINGS |
| The tool's weirdness matches its creator's brain. Use entirely at your |
| own risk. Copy files. Trace it. Become a wizard. |
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| VERSION |
| This manual page documents xxd version 1.7 |
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| AUTHOR |
| (c) 1990-1997 by Juergen Weigert |
| <jnweiger@informatik.uni-erlangen.de> |
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| Distribute freely and credit me, |
| make money and share with me, |
| lose money and don't ask me. |
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| Manual page started by Tony Nugent |
| <tony@sctnugen.ppp.gu.edu.au> <T.Nugent@sct.gu.edu.au> |
| Small changes by Bram Moolenaar. Edited by Juergen Weigert. |
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| Manual page for xxd August 1996 XXD(1) |