diff options
Diffstat (limited to 'runtime/doc/xxd.man')
| -rw-r--r-- | runtime/doc/xxd.man | 54 |
1 files changed, 28 insertions, 26 deletions
diff --git a/runtime/doc/xxd.man b/runtime/doc/xxd.man index 56b69b4341..b06971bd46 100644 --- a/runtime/doc/xxd.man +++ b/runtime/doc/xxd.man @@ -49,6 +49,8 @@ OPTIONS 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. @@ -97,15 +99,15 @@ OPTIONS 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 + lowed anywhere. Use the combination -r -b to read a bits dump instead of a hex dump. -R when - In output the hex-value and the value are both colored with the - same color depending on the hex-value. Mostly helping to differ‐ - entiate printable and non-printable characters. when is never, - always, or auto. When the $NO_COLOR environment variable is - set, colorization will be disabled. + 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 @@ -113,9 +115,9 @@ OPTIONS -s [+][-]seek Start at <seek> bytes abs. (or rel.) infile offset. + indicates - that the seek is relative to the current stdin file position + 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 + 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. @@ -125,20 +127,20 @@ OPTIONS Show version string. 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 + 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. 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) + -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. + 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 @@ -146,28 +148,28 @@ CAVEATS and % xxd -i < file - xxd -s +seek may be different from xxd -s seek, as lseek(2) is used to + 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 + 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 + 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 + 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" + % 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 + 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. EXAMPLES @@ -211,7 +213,7 @@ EXAMPLES % xxd -s 0x36 -l 13 -c 13 xxd.1 0000036: 3235 7468 204d 6179 2031 3939 36 25th May 1996 - Create a 65537 byte file with all bytes 0x00, except for the last one + 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 @@ -222,11 +224,11 @@ EXAMPLES 000fffc: 0000 0000 40 ....A 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 + 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 - Use xxd as a filter within an editor such as vim(1) to hex dump a re‐ + 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 |