Last Monday while cleaning up some old branches, I pruned a feature branch that I was working on and and nuked a week’s worth of work. The fix took fifteen seconds-not because I’m a wizard, but because I finally grok git reflog.

If you’ve ever typed git reset --hard or deleted a branch and then gone Oh ****, this guide is for you.

To keep it focused: I’m covering the few reflog moves that cover 80% of everyday disasters, plus a copy-paste alias so future-you can recover even faster.

What is the reflog (30s version)

  • Git stores every change of HEAD (and each branch) in a rolling log-the reflog.
  • Entries live for 90 days by default (git config --get gc.reflogExpire).
  • The reflog is local; it doesn’t travel with your pushes or pulls.

That’s all you need to know to start rescuing things. The rest of this post shows you when and how.

The 5 Most Common “Oh-No” Moments the Reflog Fixes 📋

  1. Accidental hard reset: you ran git reset --hard and lost unpushed commits.
  2. Deleted branch: git branch -D feature-xyz-and then realised it had work in progress.
  3. Force push gone wrong: you rewrote history on main and want the pre-push state.
  4. Rebase headache: an interactive rebase went sideways and HEAD sits on the wrong commit.
  5. Detached HEAD edits: you checked out a commit, made changes, and now HEAD floats in space.

If any of these sound familiar, keep reading. We’ll fix each with one short snippet.

TL;DR Cheat-Sheet (“gundo” Alias)

Add this to your .gitconfig:

[alias]
  gundo = "!f(){ \
    git reflog --pretty='%C(yellow)%h%Creset %Cgreen%gd%Creset %s' -n $1; \
  }; f"

Usage:

git gundo           # show last 30 HEAD movements
git gundo 5         # show last 5 (faster)

Copy-paste now; thank yourself later.

Scenario 1 - Recover After git reset --hard

# Step 1: See where HEAD *was* before the reset
git gundo 3
# 9a84e2d HEAD@{0} reset: moving to 9a84e2d
# 741fcb8 HEAD@{1} commit: add login form   ← we want this

# Step 2: Jump back
git reset --hard 741fcb8

🎉 You’re back on the last good commit. Push (or re-push) as needed.

Scenario 2 - Revive a Deleted Branch

You deleted feature-linter, but the work isn’t on any remote.

git gundo | grep feature-linter
# fb0d211 HEAD@{7} checkout: moving from feature-linter to main

git checkout -b feature-linter fb0d211

The branch-and your work-are alive again.

Scenario 3 - Undo a Bad Force Push

  1. Note the hash before the push:

    git gundo 6 | grep push
# 2c6d8a0 HEAD@{2} push: force-with-lease
# 1a57b48 HEAD@{3} commit: big refactor ← safe state

  2. Reset and push:

    git reset --hard 1a57b48
git push --force-with-lease

Remote teammates breathe easy.

Scenario 4 - Abort a Messy Rebase

During an interactive rebase you realise everything is tangled:

git rebase --abort            # bail out
git gundo 4                   # find HEAD before rebase
git reset --hard <good-hash>  # or checkout, if you prefer

Scenario 5 - Save Work from a Detached HEAD

git commit -am "temp changes"
git gundo 4                   # spot the commit hash
git branch rescue-work <hash> # or merge it elsewhere

Keeping the Log Around Longer

For long-lived side projects or rare-but-critical rollbacks:

git config --global gc.reflogExpire 180.days

Now entries linger six months before garbage collection.

Reflog vs. Other Undo Tools

Tool Best for Caveat
git reflog Any local history change Local only
git stash Quick WIP snapshots Easy to forget stashes
git reset --soft Move HEAD, keep index Doesn’t help after --hard
git restore Undo file changes Newer Git (2.23+)

Reflog is the safety net underneath all the others.

Building the Habit

  1. Alias first - add gundo today; muscle memory beats Google search.
  2. Run git gundo before you panic - it’s often the fastest way to orient yourself.
  3. Share the rescue - next time you help a teammate, link them here (or show them your alias file).

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