Introduction

Rebasing the first commit means rewriting the root commit of a branch's history. Git can do this with an interactive rebase that starts from the root, and the usual command is git rebase -i --root. This is powerful, but it rewrites history, so it is safest on local branches or on shared branches only when everyone agrees on the rewrite.

Use Interactive Rebase From the Root

For ordinary history cleanup, interactive rebase starts from a commit's parent. The first commit has no parent, so the correct flag is --root.

git rebase -i --root

Git opens the interactive rebase todo list, including the first commit. From there you can:

• change pick to reword to edit the commit message
• change pick to edit to modify the commit contents
• squash later commits into the first one if needed

That is the general answer to “how do I rebase the first commit?”

Reword the First Commit Message

If you only want to change the root commit message, mark the first line as reword.

Example todo list:

reword a1b2c3d Initial commit
pick   d4e5f6g Add README
pick   h7i8j9k Add tests

After you save and exit, Git pauses so you can edit the message. When you finish, the rebase continues automatically or prompts for the next step depending on the rest of the todo list.

Edit the Contents of the First Commit

If you need to change the actual files in the first commit, mark it as edit.

edit a1b2c3d Initial commit
pick d4e5f6g Add README
pick h7i8j9k Add tests

When Git stops at that commit:

1. make the file changes you want
2. stage them
3. amend the commit
4. continue the rebase

git add .
git commit --amend
git rebase --continue

This rewrites the root commit and then reapplies later commits on top of the updated history.

If the Repository Has Only One Commit

There is an easier case. If the branch contains only one commit, you do not need rebase at all. Just amend it directly.

git add .
git commit --amend

Interactive rebase matters when there are later commits that must be replayed after the root changes.

Understand the Consequences of History Rewriting

Rebasing the first commit changes the commit ID of the root and every descendant commit after it. That means the entire branch history receives new commit hashes.

This is usually fine on:

• local feature branches
• unpublished work
• personal cleanup before opening a pull request

It is risky on:

• shared branches other people already pulled
• protected branches
• automation-sensitive branches with published references

If the rewritten branch has already been pushed, updating the remote usually requires a force push.

git push --force-with-lease

Use --force-with-lease rather than plain --force when possible because it adds a safety check against overwriting unexpected remote changes.

Make a Backup Before Large History Surgery

Rebase is safe when used carefully, but root-commit rewrites affect everything after the first commit. Creating a temporary branch first costs almost nothing and makes recovery easy.

git branch backup-before-root-rebase

If something goes wrong, you can return to the backup branch or use git reflog to recover earlier states.

Common Pitfalls

The first pitfall is trying to start the rebase from HEAD~n and forgetting that the root commit has no parent. That is exactly what --root is for.

Another issue is rewriting published history without coordinating with teammates. Everyone else then has to reconcile the rewritten branch.

Developers also forget that changing the first commit rewrites every commit after it, not just the root itself.

Finally, do not use rebase when the branch has only one commit and git commit --amend would do the job more directly.

Summary

• Use git rebase -i --root to interactively rewrite the first commit.
• Choose reword to change the root message or edit to change its contents.
• If the branch has only one commit, git commit --amend is simpler.
• Rewriting the root changes the hash of every descendant commit.
• Use a backup branch and git push --force-with-lease when updating published history.