Git

git 2.55 Reference

Applies to the git 2.55.0 build installed in koopa (app/git/2.55.0/). Every command and flag here was verified against the installed build.

For the koopa develop→main PR / conflict / tag workflow, use koopa-git. For history rewriting with git filter-repo, use git-history-surgery.

Git alias philosophy

Aliases live in opt/dotfiles/chezmoi/dot_config/git/alias. The guiding principle: an alias earns its keep by saving keystrokes on things you type constantly. Commands you'd look up once don't belong there.

Corollaries:

• No cheat-sheet entries — if you need to look it up, look it up.
• No footguns wrapped in convenience — clean -dfx nukes gitignored files (.env, build caches); stash clear destroys all stashes silently. Strip the dangerous flags or remove the alias.
• One safe force-push alias (pf = push --force-with-lease) paired with the amend aliases (u, ua, um, touch) — never bare push --force.
• Hardcoded branch names (upstream/main, origin/main) belong in project config, not a global alias.

New builtins

git history — single-commit editing without interactive rebase

Replaces the common git rebase -i HEAD~N just-to-touch-one-commit pattern:

git history fixup <commit>    # amend a commit's content
git history reword <commit>   # change a commit's message
git history split <commit>    # break a commit into smaller pieces

Shared flags: --dry-run, --update-refs=(branches|head), --empty=(drop|keep|abort). fixup additionally takes --reedit-message.

git format-rev — pretty-format revisions on demand (EXPERIMENTAL)

Warning: This command is experimental. Behavior may change without notice.

Format one revision expression per line, or resolve commit SHAs embedded in running text:

# stdin-mode=lines: one rev expr per input line
git log --format="%H" | git format-rev --stdin-mode=lines --format="%an <%ae>"

# stdin-mode=text: replace SHA-looking tokens in free-form text
git format-rev --stdin-mode=text --format="%s" < commit-message.txt

git url-parse — expose git's internal URL parser

Extract components from any URL git understands:

git url-parse https://github.com/org/repo.git
git url-parse -c host https://github.com/org/repo.git   # just the host component

Useful for scripting around git remote URLs without fragile sed/awk.

Changed behavior on existing commands

git checkout -m now auto-stashes

git checkout -m <branch> previously gave one shot at resolving conflicts if local changes overlapped with the branch diff. Now it auto-stashes first, switches, then reapplies. If reapply conflicts, the stash entry is preserved:

git checkout -m other-branch
# if conflicts after reapply:
# 1. resolve files
# 2. git stash drop   — or clear tree and git stash pop later

If local changes don't overlap with the branch diff at all, no stash is created and the switch is seamless.

git config <key>=<value> gives a helpful error

git config foo.bar=baz   # was silently wrong; now errors with:
#   hint: Did you mean: git config set foo.bar baz

The set subcommand form has been the canonical write path since git 2.43; this nudge makes the typo visible.

Sideband terminal control sequences disabled by default

Control sequences coming over the sideband from a remote (e.g. git push/fetch progress) are now stripped except for ANSI color escapes. Prevents terminal emulator glitches from malicious or buggy servers.

Hooks can run in parallel

Hook scripts defined via the configuration system can be configured to run concurrently. Useful for slow pre-commit or pre-push hook suites.

New flags on existing commands

--graph-lane-limit=<n> / log.graphLanes

Cap the number of graph lanes shown by git log --graph. Lanes over the limit are replaced with ~:

git log --graph --graph-lane-limit=10 --oneline
# or persistently:
git config --global log.graphLanes 10

Default 0 = no limit. Negative values are treated as no limit. Fixes unreadably wide graph output on repos with many long-lived branches.

--max-count-oldest=<n>

Picks the oldest N commits in a range (inverse of --max-count):

git log --max-count-oldest=5 main    # show the 5 oldest commits reachable from main
git rev-list --max-count-oldest=3 HEAD

Handy for finding the initial commits in a range without reversing the full log.

git push <remote-group>

Push to multiple remotes at once. Define a group in config:

git config remotes.all-remotes "origin backup"
git push all-remotes main   # pushes to origin then backup, same args each

Equivalent to running git push origin main && git push backup main. No special behavior beyond being a shorthand — refspecs, options, and errors behave identically to individual pushes.

git cat-file --batch inline mailmap command

Toggle mailmap use mid-batch without restarting the process:

echo "mailmap true"  | git cat-file --batch   # enable mailmap for subsequent objects
echo "mailmap false" | git cat-file --batch   # disable

Platform / daemon

fsmonitor now available on Linux

The fsmonitor daemon (fast git status via OS filesystem events) now works on Linux. Enable it the same way as on macOS/Windows:

git config core.fsmonitor true
git config core.untrackedCache true

Most useful on large repos with many files. Verify it started: git fsmonitor--daemon status.

Notable fixes

git fetch --deepen=<n> on a full clone is now a no-op. Previously it truncated the full clone's history to N commits deep — a significant footgun. Now it correctly does nothing on a non-shallow repo.

http.emptyAuth=auto now tries Negotiate (Kerberos) before falling back to manual credential prompts. Previously required explicitly setting http.emptyAuth=true for SSO/Kerberos flows to work without a prompt.