-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'\eOOO' 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.
-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.
This program comes with NO WARRANTY, to the extent permitted by law. You may redistribute copies of this program under the terms of the GNU General Public License. For more information about these matters, see the file named COPYING.
should give you access to the complete manual.