diff3(1)

diff31

Compare three files line by line

Usage

diff3 [OPTION] ... MYFILE OLDFILE YOURFILE

Overview

Compare three files line by line.

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

-A, --show-all

output all changes, bracketing conflicts

-e, --ed

output ed script incorporating changes from OLDFILE to YOURFILE into MYFILE

-E, --show-overlap

like -e, but bracket conflicts

-3, --easy-only

like -e, but incorporate only nonoverlapping changes

-x, --overlap-only

like -e, but incorporate only overlapping changes

-X

like -x, but bracket conflicts

-i

append 'w' and 'q' commands to ed scripts

-m, --merge

output actual merged file, according to -A if no other options are given

-a, --text

treat all files as text

--strip-trailing-cr

strip trailing carriage return on input

-T, --initial-tab

make tabs line up by prepending a tab

--diff-program=PROGRAM

use PROGRAM to compare files

-L, --label=LABEL

use LABEL instead of file name (can be repeated up to three times)

--help

display this help and exit

-v, --version

output version information and exit

The default output format is a somewhat human-readable representation of the changes.

The -e, -E, -x, -X (and corresponding long) options cause an ed script to be output instead of the default.

Finally, the -m (--merge) option causes diff3 to do the merge internally and output the actual merged file. For unusual input, this is more robust than using ed.

If a FILE is '-', read standard input. Exit status is 0 if successful, 1 if conflicts, 2 if trouble.

Releases

19 releases since Debian 1.1 (Buzz); the text changed 9 times.

  1. 1.1–3.0
  2. 3.1–5.0
  3. 6.0
  4. 7
  5. 8
  6. 9
  7. 10–11
  8. 12
  9. 13
  10. Arch

--diff-program since Debian 3.1 (Sarge); --help since Debian 3.1 (Sarge); --label since Debian 7 (Wheezy); --strip-trailing-cr since Debian 6.0 (Squeeze); -L since Debian 7 (Wheezy).

-B until Debian 3.0 (Woody).

Author

Written by Randy Smith.

Reporting bugs

Report bugs to: [email protected]
GNU diffutils home page: <https://www.gnu.org/software/diffutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>

From diffutils 3.12-2 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.