linux xxd - ghdrako/doc_snipets GitHub Wiki

echo "0x480x45" | xxd -r

       xxd - make a hexdump or do the reverse.

       xxd -h[elp]
       xxd [options] [infile [outfile]]
       xxd -r[evert] [options] [infile [outfile]]

   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 standard output.  Moreover, it can be used to perform binary file patching.

   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 hexdump.  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) representation. The command line switches -r, -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.

   -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
          separate the output of every <bytes> bytes (two hex characters or eight bit-digits each) by a whitespace.  Specify -g 0 to suppress grouping.  <Bytes> 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 definition is written (named after the input file), unless xxd reads from stdin.

   -l len | -len len
          stop after writing <len> 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 hexadecimal dumps without line number information and without a particular column layout. Additional Whitespace and line-breaks are allowed anywhere.

   -seek offset
          When used after -r: revert with <offset> added to file positions found in hexdump.

   -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).   -  indi-
          cates 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.

   xxd -r has some builtin magic while evaluating line number information.  If the output file is seekable, then the linenumbers at the start of each hexdump 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.

   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  columns.  Here  anything
   that looks like a pair of hex-digits is interpreted.

   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 > plain_copy; xxd -s 0 > hex_copy" < 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=plain_snippet bs=1k count=1; xxd -s +128 > hex_snippet" < file

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

   Print everything but the first three lines (hex 0x30 bytes) of file.

       % xxd -s 0x30 file

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

       % xxd -s -0x30 file

   Print 120 bytes as continuous hexdump with 20 octets per line.

       % xxd -l 120 -ps -c 20 xxd.1
       2e54482058584420312022417567757374203139
       39362220224d616e75616c207061676520666f72
       20787864220a2e5c220a2e5c222032317374204d
       617920313939360a2e5c22204d616e2070616765
       20617574686f723a0a2e5c2220202020546f6e79
       204e7567656e74203c746f6e79407363746e7567

   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 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

   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

   Copy input_file to output_file and prepend 100 bytes of value 0x00.

       % xxd input_file | xxd -r -s 100 > output_file

   Patch the date in the file xxd.1
   
   Convert the binary file into a hexdump ( remove annoying newlines because output line feeds at regular intervals to make the output human-readable.Line feeds in the original data will be in hex form, and will remain unaffected)

    xxd -p /path/file.bin | tr -d '\n' > /path/file.hex

  Convert hex to binary format       

 xxd -r -p input.txt output.bin     
 echo 01: 01 02 03 04 | xxd -r >output.bin