Lesson 12 of 20

6 mins read

Commit Amending & Interactive Rebase (git rebase -i)

In Plain English

Before pushing code for review, developers clean up local commits. git commit --amend combines staged edits into the most recent commit or updates its message. git rebase -i allows squashing, rewording, dropping, reordering, and editing historical commits.

The Mental Model

"Interactive rebase is like an author doing a final copy-editing pass on a novel manuscript: merging two small paragraphs into one (squash), fixing a spelling mistake (reword), or deleting an unnecessary paragraph (drop)."

Deep Dive: How It Works

git commit --amend: Replaces the tip commit with a new commit containing current staged changes.

Rebase Commands: pick (keep), reword (edit message), squash (melt into previous commit), fixup (squash & discard message), drop (delete).

Linear History: Rebase replays commits on top of another base branch, eliminating merge bubbles.

Syntax Blueprint

git commit --amend -m "feat: corrected message"
git rebase -i HEAD~3
# Replay and squash commits interactively

Amend latest commit in place or launch interactive rebase editor over the last 3 commits.

Core Rules to Remember

Fixup Commits: git commit --fixup <SHA> paired with git rebase -i --autosquash automates commit squashing.

The Golden Rule of Rebase: Never rebase commits that have already been pushed to a shared public branch.

Clean Git Logs: Squashes intermediate "typo fix" and "WIP" noise into clean, meaningful atomic commits.

Common Beginner Traps & How to Fix Them

Mistake:Rebasing shared main or master branches.

Why it happens: Generates new SHA hashes for existing commits, forcing teammates into divergent merge conflicts.

How to fix: Only rebase private local feature branches before merging.

Pro Tip: Use git commit --amend --no-edit to quickly stage a forgotten file into the previous commit without retyping the message.

Live Interactive Example

Hit Run Code to see it live

Amend Commit in Place

Git 2.45 / CLI

Output Console

Click "Run Code" to view the rendered output.

How it works: git commit --amend replaces the old commit object with a new commit containing both files.

Your Turn: Micro Challenge

No pressure! Edit the starter code below and test your solution with instant feedback.

Micro Exercise

Amend Latest Commit Message

Amend the latest commit message to "feat(core): initialize kernel runtime" using "git commit --amend -m".
Display the updated log with "git log --oneline".

Sandbox Output

Click "Run & Check" to test your solution.

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