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.
Treat all files as text and compare them line-by-line, even if they do not seem to be text. See Binary Files and Forcing Text Comparisons.
Ignore changes in amount of white space. See Suppressing Differences in Blank and Tab Spacing.
Ignore changes that just insert or delete blank lines. See Suppressing Differences Whose Lines Are All Blank.
Read and write data in binary mode. See Binary Files and Forcing Text Comparisons.
Use the context output format, showing three lines of context. See Context Format.
Specify whether to use color for distinguishing different contexts, like header, added or removed lines. when may be omitted, or one of:
Do not use color at all. This is the default when no –color option is specified.
Use color only if standard output is a terminal.
Always use color.
Specifying --color and no when is equivalent to --color=auto.
Use the context output format, showing lines (an integer) lines of
context, or three if lines is not given. See 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.
Use format to output a line group containing differing lines from both files in if-then-else format. See Line Group Formats.
Change the algorithm perhaps find a smaller set of changes. This makes
diff slower (sometimes much slower). See diff Performance Tradeoffs.
Make merged ‘#ifdef’ format output, conditional on the preprocessor macro name. See Merging Files with If-then-else.
Make output that is a valid ed script. See ed Scripts.
Ignore changes due to tab expansion. See Suppressing Differences in Blank and Tab Spacing.
Make output that looks vaguely like an ed script but has changes
in the order they appear in the file. See Forward ed Scripts.
In context and unified format, for each hunk of differences, show some of the last preceding line that matches regexp. See Showing Lines That Match Regular Expressions.
Compare file to each operand; file may be a directory.
Output a summary of usage and then exit.
Do not discard the last lines lines of the common prefix
and the first lines lines of the common suffix.
See diff Performance Tradeoffs.
Ignore changes in case; consider upper- and lower-case letters equivalent. See Suppressing Case Differences.
Ignore changes that just insert or delete lines that match regexp. See Suppressing Differences Whose Lines All Match a Regular Expression.
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. See Comparing Directories.
Pass the output through pr to paginate it. See Paginating diff Output.
Use label instead of the file name in the context format (see Context Format) and unified format (see Unified Format) headers. See RCS Scripts.
Print only the left column of two common lines in side by side format. See Controlling Side by Side Format.
Use format to output all input lines in if-then-else format. See Line Formats.
Output RCS-format diffs; like -f except that each command specifies the number of lines affected. See RCS Scripts.
If one file is missing, treat it as present but empty. See Comparing Directories.
Use format to output a group of lines taken from just the second file in if-then-else format. See Line Group Formats.
Use format to output a line taken from just the second file in if-then-else format. See Line Formats.
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.
Use format to output a group of lines taken from just the first file in if-then-else format. See Line Group Formats.
Use format to output a line taken from just the first file in if-then-else format. See Line Formats.
Show which C function each change is in. See Showing C Function Headings.
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.
Report only whether the files differ, not the details of the differences. See Summarizing Which Files Differ.
When comparing directories, recursively compare any subdirectories found. See Comparing Directories.
Report when two files are the same. See Comparing Directories.
When comparing directories, start with the file file. This is used for resuming an aborted comparison. See Comparing Directories.
Use heuristics to speed handling of large files that have numerous
scattered small changes. See diff Performance Tradeoffs.
Strip any trailing carriage return at the end of an input line. See Binary Files and Forcing Text Comparisons.
Do not print common lines in side by side format. See Controlling Side by Side Format.
Expand tabs to spaces in the output, to preserve the alignment of tabs in the input files. See Preserving Tab Stop Alignment.
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. See Preserving Tab Stop Alignment.
Assume that tab stops are set every columns (default 8) print columns. See Preserving Tab Stop Alignment.
Suppress any blanks before newlines when printing the representation of an empty line, when outputting normal, context, or unified format. See Omitting trailing blanks.
Compare each operand to file; file may be a directory.
Use the unified output format, showing three lines of context. See Unified Format.
Use format to output a group of common lines taken from both files in if-then-else format. See Line Group Formats.
Use format to output a line common to both files in if-then-else format. See Line Formats.
If a first file is missing, treat it as present but empty. See Comparing Directories.
Use the unified output format, showing lines (an integer) lines of
context, or three if lines is not given. See Unified Format.
For proper operation, patch typically needs at least two lines of
context.
On older systems, diff supports an obsolete option
-lines that has effect when combined with -u.
POSIX 1003.1-2001 (see Standards conformance) does not allow
this; use -U lines instead.
Output version information and then exit.
Ignore white space when comparing lines. See Suppressing Differences in Blank and Tab Spacing.
Output at most columns (default 130) print columns per line in side by side format. See Controlling Side by Side Format.
When comparing directories, ignore files and subdirectories whose basenames match pattern. See Comparing Directories.
When comparing directories, ignore files and subdirectories whose basenames match any pattern contained in file. See Comparing Directories.
Use the side by side output format. See Controlling Side by Side Format.
Ignore white space at line end. See Suppressing Differences in Blank and Tab Spacing.