diffutils: diff Options
13.1 Options to 'diff'
======================
Below is a summary of all of the options that GNU 'diff' accepts. Most
options have two equivalent names, one of which is a single letter
preceded by '-', and the other of which is a long name preceded by '--'.
Multiple single letter options (unless they take an argument) can be
combined into a single command line word: '-ac' is equivalent to '-a
-c'. Long named options can be abbreviated to any unique prefix of
their name. Brackets ([ and ]) indicate that an option takes an
optional argument.
'-a'
'--text'
Treat all files as text and compare them line-by-line, even if they
do not seem to be text. 
Binary.
'-b'
'--ignore-space-change'
Ignore changes in amount of white space. White Space.
'-B'
'--ignore-blank-lines'
Ignore changes that just insert or delete blank lines. Blank
Lines.
'--binary'
Read and write data in binary mode. Binary.
'-c'
Use the context output format, showing three lines of context.
Context Format.
'--color [=WHEN]'
Specify whether to use color for distinguishing different contexts,
like header, added or removed lines. WHEN may be omitted, or one
of:
* none Do not use color at all. This is the default when no
-color option is specified.
* auto Use color only if standard output is a terminal.
* always Always use color.
Specifying '--color' and no WHEN is equivalent to '--color=auto'.
'-C LINES'
'--context[=LINES]'
Use the context output format, showing LINES (an integer) lines of
context, or three if LINES is not given. Context Format.
For proper operation, 'patch' typically needs at least two lines of
context.
For compatibility 'diff' also supports an obsolete option syntax
'-LINES' that has effect when combined with '-c', '-p', or '-u'.
New scripts should use '-U LINES' ('-C LINES') instead.
'--changed-group-format=FORMAT'
Use FORMAT to output a line group containing differing lines from
both files in if-then-else format. Line Group Formats.
'-d'
'--minimal'
Change the algorithm perhaps find a smaller set of changes. This
makes 'diff' slower (sometimes much slower). diff
Performance.
'-D NAME'
'--ifdef=NAME'
Make merged '#ifdef' format output, conditional on the preprocessor
macro NAME. If-then-else.
'-e'
'--ed'
Make output that is a valid 'ed' script. ed Scripts.
'-E'
'--ignore-tab-expansion'
Ignore changes due to tab expansion. White Space.
'-f'
'--forward-ed'
Make output that looks vaguely like an 'ed' script but has changes
in the order they appear in the file. Forward ed.
'-F REGEXP'
'--show-function-line=REGEXP'
In context and unified format, for each hunk of differences, show
some of the last preceding line that matches REGEXP.
Specified Headings.
'--from-file=FILE'
Compare FILE to each operand; FILE may be a directory.
'--help'
Output a summary of usage and then exit.
'--horizon-lines=LINES'
Do not discard the last LINES lines of the common prefix and the
first LINES lines of the common suffix. diff Performance.
'-i'
'--ignore-case'
Ignore changes in case; consider upper- and lower-case letters
equivalent. Case Folding.
'-I REGEXP'
'--ignore-matching-lines=REGEXP'
Ignore changes that just insert or delete lines that match REGEXP.
Specified Lines.
'--ignore-file-name-case'
Ignore case when comparing file names. For example, recursive
comparison of 'd' to 'e' might compare the contents of 'd/Init' and
'e/inIt'. At the top level, 'diff d inIt' might compare the
contents of 'd/Init' and 'inIt'. Comparing Directories.
'-l'
'--paginate'
Pass the output through 'pr' to paginate it. Pagination.
'-L LABEL'
'--label=LABEL'
Context Format::) and unified format (Unified Format)
headers. RCS.
'--left-column'
Print only the left column of two common lines in side by side
format. Side by Side Format.
'--line-format=FORMAT'
Use FORMAT to output all input lines in if-then-else format.
Line Formats.
'-n'
'--rcs'
Output RCS-format diffs; like '-f' except that each command
specifies the number of lines affected. RCS.
'-N'
'--new-file'
If one file is missing, treat it as present but empty.
Comparing Directories.
'--new-group-format=FORMAT'
Use FORMAT to output a group of lines taken from just the second
file in if-then-else format. Line Group Formats.
'--new-line-format=FORMAT'
Use FORMAT to output a line taken from just the second file in
if-then-else format. Line Formats.
'--no-dereference'
Act on symbolic links themselves instead of what they point to.
Two symbolic links are deemed equal only when each points to
precisely the same name.
'--old-group-format=FORMAT'
Use FORMAT to output a group of lines taken from just the first
file in if-then-else format. Line Group Formats.
'--old-line-format=FORMAT'
Use FORMAT to output a line taken from just the first file in
if-then-else format. Line Formats.
'-p'
'--show-c-function'
Show which C function each change is in. C Function
Headings.
'--palette=PALETTE'
Specify what color palette to use when colored output is enabled.
It defaults to 'rs=0:hd=1:ad=32:de=31:ln=36' for red deleted lines,
green added lines, cyan line numbers, bold header.
Supported capabilities are as follows.
'ad=32'
SGR substring for added lines. The default is green
foreground.
'de=31'
SGR substring for deleted lines. The default is red
foreground.
'hd=1'
SGR substring for chunk header. The default is bold
foreground.
'ln=36'
SGR substring for line numbers. The default is cyan
foreground.
'-q'
'--brief'
Report only whether the files differ, not the details of the
differences. Brief.
'-r'
'--recursive'
When comparing directories, recursively compare any subdirectories
found. Comparing Directories.
'-s'
'--report-identical-files'
Report when two files are the same. Comparing Directories.
'-S FILE'
'--starting-file=FILE'
When comparing directories, start with the file FILE. This is used
for resuming an aborted comparison. Comparing Directories.
'--speed-large-files'
Use heuristics to speed handling of large files that have numerous
scattered small changes. diff Performance.
'--strip-trailing-cr'
Strip any trailing carriage return at the end of an input line.
Binary.
'--suppress-common-lines'
Do not print common lines in side by side format. Side by
Side Format.
'-t'
'--expand-tabs'
Expand tabs to spaces in the output, to preserve the alignment of
tabs in the input files. Tabs.
'-T'
'--initial-tab'
Output a tab rather than a space before the text of a line in
normal or context format. This causes the alignment of tabs in the
line to look normal. Tabs.
'--tabsize=COLUMNS'
Assume that tab stops are set every COLUMNS (default 8) print
columns. Tabs.
'--suppress-blank-empty'
Suppress any blanks before newlines when printing the
representation of an empty line, when outputting normal, context,
or unified format. Trailing Blanks.
'--to-file=FILE'
Compare each operand to FILE; FILE may be a directory.
'-u'
Use the unified output format, showing three lines of context.
Unified Format.
'--unchanged-group-format=FORMAT'
Use FORMAT to output a group of common lines taken from both files
in if-then-else format. Line Group Formats.
'--unchanged-line-format=FORMAT'
Use FORMAT to output a line common to both files in if-then-else
format. Line Formats.
'--unidirectional-new-file'
If a first file is missing, treat it as present but empty.
Comparing Directories.
'-U LINES'
'--unified[=LINES]'
Use the unified output format, showing LINES (an integer) lines of
context, or three if LINES is not given. Unified Format.
For proper operation, 'patch' typically needs at least two lines of
context.
On older systems, 'diff' supports an obsolete option '-LINES' that
Standards conformance::) does not allow this; use '-U LINES'
instead.
'-v'
'--version'
Output version information and then exit.
'-w'
'--ignore-all-space'
Ignore white space when comparing lines. White Space.
'-W COLUMNS'
'--width=COLUMNS'
Output at most COLUMNS (default 130) print columns per line in side
by side format. Side by Side Format.
'-x PATTERN'
'--exclude=PATTERN'
When comparing directories, ignore files and subdirectories whose
basenames match PATTERN. Comparing Directories.
'-X FILE'
'--exclude-from=FILE'
When comparing directories, ignore files and subdirectories whose
basenames match any pattern contained in FILE. Comparing
Directories.
'-y'
'--side-by-side'
Use the side by side output format. Side by Side Format.
'-Z'
'--ignore-trailing-space'
Ignore white space at line end. White Space.
Info Catalog
diffutils: Invoking diff