Scroll to navigation

DIFF(1) User Commands DIFF(1)


diff - compare files line by line


diff [OPTION]... FILES


Compare FILES line by line.

Mandatory arguments to long options are mandatory for short options too.

output a normal diff (the default)
report only when files differ
report when two files are the same
output NUM (default 3) lines of copied context
output NUM (default 3) lines of unified context
output an ed script
output an RCS format diff
output in two columns
output at most NUM (default 130) print columns
output only the left column of common lines
do not output common lines
show which C function each change is in
-F, --show-function-line=RE
show the most recent line matching RE
use LABEL instead of file name and timestamp (can be repeated)
expand tabs to spaces in output
make tabs line up by prepending a tab
tab stops every NUM (default 8) print columns
suppress space or tab before empty output lines
pass output through 'pr' to paginate it
recursively compare any subdirectories found
don't follow symbolic links
-N, --new-file
treat absent files as empty
treat absent first files as empty
ignore case when comparing file names
consider case when comparing file names
exclude files that match PAT
exclude files that match any pattern in FILE
start with FILE when comparing directories
compare FILE1 to all operands; FILE1 can be a directory
compare all operands to FILE2; FILE2 can be a directory
ignore case differences in file contents
-E, --ignore-tab-expansion
ignore changes due to tab expansion
ignore white space at line end
ignore changes in the amount of white space
ignore all white space
ignore changes where lines are all blank
ignore changes where all lines match RE
treat all files as text
strip trailing carriage return on input
output merged file with '#ifdef NAME' diffs
format GTYPE input groups with GFMT
format all input lines with LFMT
format LTYPE input lines with LFMT
These format options provide fine-grained control over the output
of diff, generalizing -D/--ifdef.
GTYPE is LTYPE or 'changed'.
GFMT (only) may contain:
lines from FILE1
lines from FILE2
lines common to FILE1 and FILE2
printf-style spec for LETTER
LETTERs are as follows for new group, lower case for old group:
first line number
last line number
number of lines = L-F+1
if A equals B then T else E
LFMT (only) may contain:
contents of line
contents of line, excluding any trailing newline
printf-style spec for input line number
Both GFMT and LFMT may contain:
the single character C
the character with octal code OOO
the character C (other characters represent themselves)
try hard to find a smaller set of changes
keep NUM lines of the common prefix and suffix
assume large files and many scattered small changes
color output; WHEN is 'never', 'always', or 'auto'; plain --color means --color='auto'
the colors to use when --color is active; PALETTE is a colon-separated list of terminfo capabilities
display this help and exit
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.


Written by Paul Eggert, Mike Haertel, David Hayes, Richard Stallman, and Len Tower.


Report bugs to:
GNU diffutils home page: <>
General help using GNU software: <>


Copyright © 2023 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.


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.

May 2023 diffutils 3.10