NAME

       diff - compare files line by line

SYNOPSIS

       diff [OPTION]... FILES

DESCRIPTION

       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

       -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 whose lines are all blank

       -I, --ignore-matching-lines=RE
              ignore changes whose lines all 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.

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  ©  2011  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

       wdiff(1), cmp(1), diff3(1), sdiff(1), patch(1)

       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.