Manual Pages for UNIX Darwin command on man xxd

XXD(1) XXD(1)

NAME

xxd - make a hexdump or do the reverse.

SYNOPSIS

xxxxdd -h[elp]

xxxxdd [options] [infile [outfile]]

xxxxdd -r[evert] [options] [infile [outfile]]

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 uuuueennccooddee((11))

and uuuuddeeccooddee((11)) 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. OOPPTTIIOONNSS 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 -cc88, -cc 88, -cc 001100 and -ccoollss 88 are all equivalent.

-a | -autoskip

toggle autoskip: A single '*' replaces nul-lines. Default off.

-b | -bits

Switch to bits (binary digits) dump, rather than hexdump. This option writes octets as eight digits "1"s and "0"s instead of a normal hexacecimal dump. Each line is preceded by a line number

in hexadecimal and followed by an ascii (or ebcdic) representa-

tion. The command line switches -r, -p, -i do not work with this

mode.

-c cols | -cols cols

-c cols | -cols cols format octets per line. Default 16

(-i: 12, -ps: 30, -b: 6). Max 256.

-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.

-g bytes | -groupsize bytes

seperate the output of every bytes (two hex characters

or eight bit-digits each) by a whitespace. Specify -g 0 to sup-

press grouping. defaults to 2 in normal 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 octets.

-p | -ps | -postscript | -plain

output in postscript continuous hexdump style. Also known as plain hexdump style.

-r | -revert

reverse operation: convert (or patch) hexdump 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

allowed anywhere.

-seek offset

When used after -r : revert with added to file posi-

tions found in hexdump.

-s [+][-]seek

start at 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.

-v | -version

show version string. CCAAVVEEAATTSS

xxd -r has some builtin magic while evaluating line number information.

If the ouput file is seekable, then the linenumbers at the start of

each hexdump line may be out of order, lines may be missing, or over-

lapping. 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.

xxd -r never generates parse errors. Garbage is silently skipped.

When editing hexdumps, 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

hexdump with xxd -r -p does not depend on the correct number of col-

umns. Here an thing that looks like a pair of hex-digits is inter-

preted. Note the difference between

% xxd -i file

and

% xxd -i < file

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 > plaincopy; xxd -s 0 > hexcopy' < file

Hexdump 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=plainsnippet bs=1k count=1; xxd -s +128 > hexsnippet'

< file

Hexdump from file position 0x100 ( = 1024-768) on.

% sh -c 'dd of=plainsnippet bs=1k count=1; xxd -s +-768 > hexsnippet'

< 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.

EEXXAAMMPPLLEESS Print everything but the first three lines (hex 0x30 bytes) of ffiillee

% xxd -s 0x30 file

Print 3 lines (hex 0x30 bytes) from the end of ffiillee

% xxd -s -0x30 file

Print 120 bytes as continuous hexdump with 40 octets per line.

% xxd -l 120 -ps -c 20 xxd.1

2e544820585844203120224d616e75616c207061 676520666f7220787864220a2e5c220a2e5c2220 32317374204d617920313939360a2e5c22204d61 6e207061676520617574686f723a0a2e5c222020 2020546f6e79204e7567656e74203c746f6e7940 7363746e7567656e2e7070702e67752e6564752e Hexdump 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 224d .TH XXD 1 "M 000000c: 616e 7561 6c20 7061 6765 2066 anual page f

0000018: 6f72 2078 7864 220a 2e5c 220a or xxd"..\".

0000024: 2e5c 2220 3231 7374 204d 6179 .\" 21st May 0000030: 2031 3939 360a 2e5c 2220 4d61 1996..\" Ma 000003c: 6e20 7061 6765 2061 7574 686f n page autho 0000048: 723a 0a2e 5c22 2020 2020 546f r:..\" To 0000054: 6e79 204e 7567 656e 7420 3c74 ny Nugent Display just the date from the file xxd.1

% xxd -s 0x28 -l 12 -c 12 xxd.1

0000028: 3231 7374 204d 6179 2031 3939 21st May 199 Copy iinnppuuttffiillee to oouuttppuuttffiillee and prepend 100 bytes of value 0x00.

% xxd inputfile | xxd -r -s 100 > outputfile

Patch the date in the file xxd.1

% echo '0000029: 3574 68' | xxd -r - xxd.1

% xxd -s 0x28 -l 12 -c 12 xxd.1

0000028: 3235 7468 204d 6179 2031 3939 25th May 199 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

Hexdump this file with autoskip.

% xxd -a -c 12 file

0000000: 0000 0000 0000 0000 0000 0000 ............ * 000fffc: 0000 0000 40 ....A Create a 1 byte file containing a single 'A' character. The number

after '-r -s' adds to the linenumbers found in the file; in effect, the

leading bytes are suppressed.

% echo '010000: 41' | xxd -r -s -0x10000 > file

Use xxd as a filter within an editor such as vviimm((11)) to hexdump a region

marked between `a' and `z'.

:'a,'z!xxd

Use xxd as a filter within an editor such as vviimm((11)) to recover a binary

hexdump marked between `a' and `z'.

:'a,'z!xxd -r

Use xxd as a filter within an editor such as vviimm((11)) to recover one line

of a hexdump. Move the cursor over the line and type:

!!xxd -r

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

RETURN VALUES

The following error values are returned: 0 no errors encountered.

-1 operation not supported ( xxd -r -i still impossible).

1 error while parsing options. 2 problems with input file. 3 problems with output file. 4,5 desired seek position is unreachable.

This manual page documents xxd version 1.7

AUTHOR

Distribute freely and credit me, make money and share with me, lose money and don't ask me. Manual page started by Tony Nugent Small changes by Bram Moolenaar. Edited by Juergen Weigert.