-q, --brief report only when files differ
-s, --report-identical-files report when two files are the same
-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
-e, --ed output an ed script
-n, --rcs output an RCS format diff
-y, --side-by-side output in two columns
-W, --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
-p, --show-c-function show which C function each change is in
-F, --show-function-line=RE show the most recent line matching RE
--label LABEL use LABEL instead of file name
(can be repeated)
-t, --expand-tabs expand tabs to spaces in output
-T, --initial-tab make tabs line up by prepending a tab
--tabsize=NUM tab stops every NUM (default 8) print columns
--suppress-blank-empty suppress space or tab before empty output lines
-l, --paginate pass output through `pr' to paginate it
-r, --recursive recursively compare any subdirectories found
-N, --new-file treat absent files as empty
--unidirectional-new-file treat absent first files as empty
