Git History Cleanup Guide

This guide explains how to remove specific commits from Git history while preserving later commits.

Current Situation

Initial repository state has 4 commits:

4. abcd (latest)
3. abcc
2. abcb
1. abca (oldest)

Objective

Remove commits abca and abcb while preserving abcc and abcd.

Instructions

1. Start Interactive Rebase

git rebase -i HEAD~4

2. Edit Rebase File

When your editor opens, you'll see something like this:

pick abca first commit
pick abcb second commit
pick abcc third commit
pick abcd fourth commit

Change it to:

drop abca first commit
drop abcb second commit
pick abcc third commit
pick abcd fourth commit

3. Save and Complete

1. Save the file and close your editor
2. Git will automatically process the rebase

4. Push Changes

If this is a local-only repository:

git push

If you've already pushed these commits to a remote repository:

git push --force

⚠️ Important Warnings

1. This operation rewrites Git history
2. Using --force push can be dangerous in shared repositories
3. Always backup your repository before performing history-altering operations
4. Coordinate with your team before modifying shared history

Best Practices

1. Make sure you have no uncommitted changes before starting
2. Create a backup branch before proceeding:

   git branch backup-before-rebase
3. Inform team members before force pushing to shared repositories
4. Consider using git push --force-with-lease instead of --force for added safety

Troubleshooting

If something goes wrong during the rebase:

1. To abort the rebase:

   git rebase --abort
2. To restore from backup:

   git checkout backup-before-rebase