diff (GNU diffutils) 3.3 Copyright (C) 2013 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.  Written by Paul Eggert, Mike Haertel, David Hayes, Richard Stallman, and Len Tower.

Usage: diff [OPTION]... FILES Compare FILES line by line.  Mandatory arguments to long options are mandatory for short options too. --normal output a normal diff (the default) -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 --no-dereference don't follow symbolic links -N, --new-file treat absent files as empty --unidirectional-new-file treat absent first files as empty --ignore-file-name-case ignore case when comparing file names --no-ignore-file-name-case consider case when comparing file names -x, --exclude=PAT exclude files that match PAT -X, --exclude-from=FILE exclude files that match any pattern in FILE -S, --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  -i, --ignore-case ignore case differences in file contents -E, --ignore-tab-expansion ignore changes due to tab expansion -Z, --ignore-trailing-space ignore white space at line end -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 where lines are all blank -I, --ignore-matching-lines=RE ignore changes where all lines match RE  -a, --text treat all files as text --strip-trailing-cr strip trailing carriage return on input  -D, --ifdef=NAME output merged file with '#ifdef NAME' diffs --GTYPE-group-format=GFMT format GTYPE input groups with GFMT --line-format=LFMT format all input lines with LFMT --LTYPE-line-format=LFMT format LTYPE input lines with LFMT These format options provide fine-grained control over the output of diff, generalizing -D/--ifdef. LTYPE is 'old', 'new', or 'unchanged'. GTYPE is LTYPE or 'changed'. GFMT (only) 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 %(A=B?T:E) if A equals B then T else E LFMT (only) 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 Both GFMT and LFMT may contain: %% % %c'C' the single character C %c'\OOO' the character with octal code OOO C the character C (other characters represent themselves)  -d, --minimal try hard to find a smaller set of changes --horizon-lines=NUM keep NUM lines of the common prefix and suffix --speed-large-files assume large files and many scattered small changes  --help display this help and exit -v, --version output version information and exit  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 FILE(s). If a FILE is '-', read standard input. Exit status is 0 if inputs are the same, 1 if different, 2 if trouble.  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/>