diff - find differences between two files
diff [ options ] from-file to-file
In the simplest case, diff
compares the contents of the two files from-file
. A file name of -
stands for text read from the standard input. As a special case, diff - -
compares a copy of standard input to itself.
If from-file is a directory and to-file is not, diff compares the file in from-file whose file name is
that of to-file, and vice versa. The non-directory file must not be -.
If both from-file and to-file are directories, diff compares corresponding files in both directories, in
alphabetical order; this comparison is not recursive unless the --recursive option is given. diff never compares the
actual contents of a directory as if it were a file. The file that is fully specified may not be standard input, because standard
input is nameless and the notion of ``file with the same name'' does not apply.
- -B, --ignore-blank-lines
Ignore changes that just insert or delete blank lines.
- -C, --context=lines
Use the context output format, showing lines lines of context. For proper
operation, patch(1) typically needs at least 2 lines of context. The default
value is 3.
- -D, --ifdef=macro
Make merged if-then-else format output, conditional on the preprocessor macro
- -F, --show-function-line=pattern
In context and unified format, for each hunk of differences, show some
of the last preceding line that matches the regular expression pattern.
- -H, --speed-large-files
Use heuristics to speed handling of large files that have numerous scattered small
- -I, --ignore-matching-lines=pattern
Ignore changes that just insert or delete lines that match the
regular expression pattern.
- -L, --label|file-label=label
Use label instead of the file name in the context format and
unified format headers.
- -N, --new-file|entire-new-file
In directory comparison, if a file is found in only one directory, treat it as
present but empty in the other directory.
- -P, --unidirectional-new-file
When comparing directories, if a file appears only in the second directory of
the two, treat it as present but empty in the other.
- -S, --starting-file=file
When comparing directories, start with the file file. This is for
resuming an interrupted comparison.
- -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.
- -W, --width=columns
Use an output width of columns in side by side format.
- -a, --text|ascii
Treat all files as text and compare them line-by-line, even if they do not seem to be text.
- -b, --ignore-space-change
Ignore changes in amount of white space.
- -d, --minimal
Change the algorithm to perhaps find a smaller set of changes. This makes diff slower
(sometimes much slower).
- -e, --ed
Make output that is a valid ed(1) script.
- -f, --forward-ed
Make output that looks vaguely like an
ed(1) script but has changes in the order they appear in the file.
- -i, --ignore-case
Ignore changes in case; consider upper- and lower-case letters equivalent.
- -l, --paginate|print
Pass the output through pr(1) to
- -n, --rcs
Output rcs(1) format diffs; like --forward-ed
except that each command specifies the number of lines affected.
- -p, --show-c-function
Show which C function each change is in.
- -q, --brief
Report only whether the files differ, not the details of the differences.
- -r, --recursive
When comparing directories, recursively compare any subdirectories found.
- -s, --report-identical-files
Report when two files are the same.
- -t, --expand-tabs
Expand tabs to spaces in the output, to preserve the alignment of tabs in the input files.
- -w, --ignore-all-space
Ignore white space when comparing lines.
- -x, --exclude=pattern
When comparing directories, ignore files and subdirectories whose basenames match
the sh(1) file match pattern.
- -X, --exclude-from=file
When comparing directories, ignore files and subdirectories whose basenames
match any pattern contained in file, where each is taken to be one sh(1)
file match pattern.
- -y, --side-by-side
Use the side by side output format.
- -U, --unified[=lines]
Use the unified output format, showing lines lines of context. For proper
operation patch(1) typically needs at least 2 lines of context. The option
value may be omitted. The default value is 3.
Print only the left column of two common lines in side by side format.
Do not print common lines in side by side format.
Print extra information to help sdiff(1).
Not intended for other use besides sdiff.
Use format to output a line taken from just the first file in if-then-else
Use format to output a line taken from just the second file in if-then-else
Use format to output a line common to both files in if-then-else
Use format to output all input lines in if-then-else format.
Use format to output a group of lines taken from just the first file in if-then-else
Use format to output a group of lines taken from just the second file in if-then-else
Use format to output a group of common lines taken from both files in
Use format to output a line group containing differing lines from both
files in if-then-else format.
Do not discard the last lines lines of the common prefix and the first lines
lines of the common suffix.
Read and write data in binary mode. Ignored on some systems.
- Equivalent to --context=3.
- Ignored by this implementation.
- Equivalent to --unified=3.
- Print the program version and exit.
- No differences were found.
- Some differences were found.
- An error occurred.