linux man page for diff

DIFF(1) 							   User Commands							   DIFF(1)

NAME
       diff - compare files line by line

SYNOPSIS
       diff [OPTION]... FILES

DESCRIPTION
       Compare files line by line.

       -i  --ignore-case
	      Ignore case differences in file contents.

       --ignore-file-name-case
	      Ignore case when comparing file names.

       --no-ignore-file-name-case
	      Consider case when comparing file names.

       -E  --ignore-tab-expansion
	      Ignore changes due to tab expansion.

       -b  --ignore-space-change
	      Ignore changes in the amount of white space.

       -w  --ignore-all-space
	      Ignore all white space.

       -B  --ignore-blank-lines
	      Ignore changes whose lines are all blank.

       -I RE  --ignore-matching-lines=RE
	      Ignore changes whose lines all match RE.

       --strip-trailing-cr
	      Strip trailing carriage return on input.

       -a  --text
	      Treat all files as text.

       -c  -C NUM  --context[=NUM]
	      Output NUM (default 3) lines of copied context.

       -u  -U NUM  --unified[=NUM]
	      Output NUM (default 3) lines of unified context.

       --label LABEL
	      Use LABEL instead of file name.

       -p  --show-c-function
	      Show which C function each change is in.

       -F RE  --show-function-line=RE
	      Show the most recent line matching RE.

       -q  --brief
	      Output only whether files differ.

       -e  --ed
	      Output an ed script.

       --normal
	      Output a normal diff.

       -n  --rcs
	      Output an RCS format diff.

       -y  --side-by-side
	      Output in two columns.

       -W NUM  --width=NUM
	      Output at most NUM (default 130) print columns.

       --left-column
	      Output only the left column of common lines.

       --suppress-common-lines
	      Do not output common lines.

       -D NAME	--ifdef=NAME
	      Output merged file to show `#ifdef NAME' diffs.

       --GTYPE-group-format=GFMT
	      Similar, but format GTYPE input groups with GFMT.

       --line-format=LFMT
	      Similar, but format all input lines with LFMT.

       --LTYPE-line-format=LFMT
	      Similar, but format LTYPE input lines with LFMT.

       LTYPE is `old', `new', or `unchanged'.
	      GTYPE is LTYPE or `changed'.

	      GFMT may contain:

       %<     lines from FILE1

       %>     lines from FILE2

       %=     lines common to FILE1 and FILE2

       %[-][WIDTH][.[PREC]]{doxX}LETTER
	      printf-style spec for LETTER

	      LETTERs are as follows for new group, lower case for old group:

       F      first line number

       L      last line number

       N      number of lines = L-F+1

       E      F-1

       M      L+1

	      LFMT may contain:

       %L     contents of line

       %l     contents of line, excluding any trailing newline

       %[-][WIDTH][.[PREC]]{doxX}n
	      printf-style spec for input line number

	      Either GFMT or LFMT may contain:

       %%     %

       %c'C'  the single character C

       %c'OOO'
	      the character with octal code OOO

       -l  --paginate
	      Pass the output through `pr' to paginate it.

       -t  --expand-tabs
	      Expand tabs to spaces in output.

       -T  --initial-tab
	      Make tabs line up by prepending a tab.

       --tabsize=NUM
	      Tab stops are every NUM (default 8) print columns.

       --suppress-blank-empty
	      Suppress space or tab before empty output lines.

       -r  --recursive
	      Recursively compare any subdirectories found.

       -N  --new-file
	      Treat absent files as empty.

       --unidirectional-new-file
	      Treat absent first files as empty.

       -s  --report-identical-files
	      Report when two files are the same.

       -x PAT  --exclude=PAT
	      Exclude files that match PAT.

       -X FILE	--exclude-from=FILE
	      Exclude files that match any pattern in FILE.

       -S FILE	--starting-file=FILE
	      Start with FILE when comparing directories.

       --from-file=FILE1
	      Compare FILE1 to all operands.  FILE1 can be a directory.

       --to-file=FILE2
	      Compare all operands to FILE2.  FILE2 can be a directory.

       --horizon-lines=NUM
	      Keep NUM lines of the common prefix and suffix.

       -d  --minimal
	      Try hard to find a smaller set of changes.

       --speed-large-files
	      Assume large files and many scattered small changes.

       -v  --version
	      Output version info.

       --help Output this help.

       FILES  are `FILE1 FILE2' or `DIR1 DIR2' or `DIR FILE...' or `FILE... DIR'.  If --from-file or --to-file is given, there are no restrictions
       on FILES.  If a FILE is `-', read standard input.  Exit status is 0 if inputs are the same, 1 if different, 2 if trouble.

AUTHOR
       Written by Paul Eggert, Mike Haertel, David Hayes, Richard Stallman, and Len Tower.

REPORTING BUGS
       Report bugs to: bug-diffutils@gnu.org GNU diffutils home page: <http://www.gnu.org/software/diffutils/> General help  using  GNU  software:
       <http://www.gnu.org/gethelp/>

COPYRIGHT
       Copyright (C) 2010 Free Software Foundation, Inc.  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
       This is free software: you are free to change and redistribute it.  There is NO WARRANTY, to the extent permitted by law.

SEE ALSO
       The  full documentation for diff is maintained as a Texinfo manual.  If the info and diff programs are properly installed at your site, the
       command

	      info diff

       should give you access to the complete manual.

diffutils 2.9.19-4065						    April 2010								   DIFF(1)