Interactive Rebasing, Git Reflog, and Disaster Recovery

Git almost never deletes commit data immediately. Even if you accidentally run git reset --hard HEAD~5 or delete a branch with unpushed commits, git reflog preserves all local pointer movements. This guide covers Interactive Rebasing (rebase -i), Disaster Recovery with Reflog, Cherry-Picking, and Bisect debugging.

⚡ Quick Dive

Interactive Rebase Commands Cheat Sheet (git rebase -i HEAD~4)

Action Command Purpose
pick pick a1b2c3d Keep the commit as-is
reword reword a1b2c3d Edit the commit message
edit edit a1b2c3d Pause rebase to amend files or split into multiple commits
squash squash a1b2c3d Meld commit into previous commit; prompts to combine messages
fixup fixup a1b2c3d Meld commit into previous commit; silently discards this message
drop drop a1b2c3d Remove the commit entirely

📖 Extended Guide

1. Disaster Recovery with git reflog

If you accidentally run git reset --hard and lose all your work:

# 1. View local reference log of every HEAD change
git reflog

# Output:
# a1b2c3d HEAD@{0}: reset: moving to HEAD~5 (Catastrophe!)
# 9f8e7d6 HEAD@{1}: commit: Completed important payment feature (Lost commit!)

# 2. Restore exact state prior to the hard reset
git reset --hard HEAD@{1} # Or: git branch recovered-feature 9f8e7d6

2. Binary Search Debugging with git bisect

Find the exact commit that introduced a regression in $O(\log N)$ time:

git bisect start
git bisect bad                 # Current commit has the bug
git bisect good v1.4.0         # Last known good release

# Git checks out middle commit automatically. Run tests:
npm test                       # If fails: git bisect bad | If passes: git bisect good

git bisect reset               # Done!
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