Man1 - diff3.1

Table of Contents


diff3 - compare three files line by line




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
like -x, but bracket conflicts
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 carriage return on input
-T, –initial-tab
make tabs line up by prepending a tab
use PROGRAM to compare files
-L, *–label*=/LABEL/
use LABEL instead of file name (can be repeated up to three times)
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.


Written by Randy Smith.


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


Copyright © 2021 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.


cmp(1), diff(1), sdiff(1)

The full documentation for diff3 is maintained as a Texinfo manual. If the info and diff3 programs are properly installed at your site, the command

info diff3

should give you access to the complete manual.

Author: dt

Created: 2022-02-22 Tue 16:43