DIFF3(1)

📦
version 3.12 · 11 versions
, in alpine 3.22, alpine 3.23, alpine 3.24, arch rolling, fedora 43, fedora 44, nixos 26.05, nixpkgs unstable, opensuse-leap 16.0, ubuntu resolute

💖 diff3(1) — the girlies' guide to three-way file comparison 💖

okay so bestie, welcome to diff3, a real one from the User Commands section of the manual. this is the tool you call when you've got three versions of the same file and you need to know who changed what. no cap, it's iconic. 💅

✨ NAME ✨

diff3 — compare three files line by line 🦋

🌸 SYNOPSIS 🌸

diff3 [OPTION]... MYFILE OLDFILE YOURFILE

💜 DESCRIPTION 💜

okay so the whole vibe is: you feed it three files, it compares them line by line. that's the entire job. simple. slay. ⭐

also, real talk: mandatory arguments to long options are mandatory for short options too. meaning if a long option needs a value, its short twin needs one too. periodt. 🎀

✨ OPTIONS ✨ (the whole menu, bestie, nothing skipped)

  • -A, --show-all — spits out all the changes, and wraps the conflicts in brackets so you can spot them 👀
  • -e, --ed — outputs an ed script that folds the changes going from OLDFILE to YOURFILE straight into MYFILE
  • -E, --show-overlap — literally like -e, except it brackets the conflicts 💀
  • -3, --easy-only — like -e, but only incorporates the changes that don't overlap. easy mode fr fr
  • -x, --overlap-only — like -e, but only incorporates the changes that do overlap
  • -X — like -x, but it brackets conflicts
  • -i — appends w and q commands onto the ed scripts
  • -m, --merge — outputs the actual merged file, and it behaves according to -A if you didn't give it any other options
  • -a, --text — treats all the files as text, no matter what they look like
  • --strip-trailing-cr — strips the trailing carriage return off the input
  • -T, --initial-tab — makes tabs line up by prepending a tab
  • --diff-program=PROGRAM — uses PROGRAM to compare the files
  • -L, --label=LABEL — uses LABEL instead of the file name (you can repeat this up to three times)
  • --help — displays this help and dips out
  • -v, --version — outputs version info and dips out

🦋 the output formats, explained 🦋

so by default, the output format is a somewhat human-readable representation of the changes. that's the default vibe, that's what you get if you ask for nothing. ✨

the -e, -E, -x, -X options — and their long-option twins — make it output an ed script instead of that default. iykyk.

and finally, the -m (--merge) option makes diff3 do the merge internally and output the actual merged file. for unusual input, this is more robust than using ed. lowkey a glow-up. 👑

🙈 the fine print, don't skip it 🙈

if a FILE is -, it reads from standard input. bestie please remember this one.

exit status is:

  • 0 — if successful 🫶
  • 1 — if conflicts 😭
  • 2 — if trouble 💀

⭐ AUTHOR ⭐

Written by Randy Smith. king behavior, honestly.

📮 REPORTING BUGS 📮

found a bug? don't be shy, tell the maintainers:

Copyright © 2025 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.

this is free software: you are free to change and redistribute it. there is NO WARRANTY, to the extent permitted by law.

👑 SEE ALSO 👑

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. go read it, it's giving scholar. 📚✨

and that's the whole page, bestie 🎀 this one came from diffutils 3.12, dated April 2025 — mwah, sending you off with that footer energy. bye bestie, go merge something 💖🦋🌸

📦 where this page comes from