What is Git Rebase?

Git rebase is a command used to integrate changes from one branch into another. Unlike the git merge command, which combines commits into a new “merge commit,” git rebase rewrites commit history by changing the base of your branch, allowing you to replay your changes on top of another branch.

While git rebase is often used to update feature branches with the latest changes from the main branch (e.g., master or main), an interactive rebase provides more granular control over the commit history, enabling you to reorder, squash, or modify commits.

What is an Interactive Rebase?

An interactive rebase in Git allows you to modify a series of commits in your branch before pushing them to a remote repository. This operation is especially useful for cleaning up a commit history by:

• Reordering commits
• Squashing multiple commits into one
• Fixing commit messages
• Editing content of commits
• Dropping unwanted commits

Interactive rebasing is done using the git rebase -i command, which opens up a text editor to allow you to select which commits to modify. The command is particularly helpful when working in a team environment where you want to make sure your commit history is clean and logical before pushing changes to a shared repository.

Why Use Interactive Rebase?

There are several reasons why you might want to use interactive rebase in Git:

• Cleanup Commit History: If your commit history contains messy or unnecessary commits, interactive rebase lets you squash or drop them for a cleaner, more readable history.
• Reorder Commits: You can reorder your commits to ensure that related changes appear together or to correct the logical flow of changes in the history.
• Improve Commit Messages: Interactive rebase allows you to edit commit messages for clarity or to follow the project’s contribution guidelines.
• Fix Bugs: You can modify specific commits to fix bugs or improve functionality without disrupting the rest of your work.

How to Perform an Interactive Rebase in Git?

Here’s a step-by-step guide to performing an interactive rebase in Git:

1. Start an Interactive Rebase

To begin an interactive rebase, use the following command:

git rebase -i 

In this command, replace with the commit hash of the commit you want to rebase onto. If you want to rebase the last N commits, you can specify the number of commits:

git rebase -i HEAD~n

This command will open a text editor with a list of commits that are available for rebasing. By default, Git will display the last N commits in reverse order (oldest commit at the bottom). Each commit will be prefixed with the word “pick”.

2. Edit the Rebase Instructions

In the text editor, you’ll see a list of commits that look something like this:

pick abc1234 Commit message 1
pick def5678 Commit message 2
pick ghi9012 Commit message 3
        

You can change the command next to each commit to instruct Git on how to handle each commit:

• pick: Use the commit as it is.
• reword: Edit the commit message.
• edit: Pause the rebase process and allow you to modify the commit content.
• squash: Combine the commit with the previous one.
• fixup: Like squash, but discards the commit message.
• drop: Remove the commit entirely.

For example, to squash the second commit into the first, change the word “pick” to “squash” or “fixup” for the second commit:

pick abc1234 Commit message 1
squash def5678 Commit message 2
pick ghi9012 Commit message 3
        

3. Save and Close the Editor

Once you’ve made the necessary changes, save the file and close the text editor. Git will begin the rebase process, applying each commit according to the instructions you specified.

4. Resolve Conflicts (If Any)

If there are any conflicts during the rebase, Git will stop and prompt you to resolve them. After resolving conflicts in the affected files, stage the changes:

git add 

Then continue the rebase process by running:

git rebase --continue

If you want to cancel the rebase at any point, you can run:

git rebase --abort

5. Finish the Rebase

Once the rebase is complete, Git will prompt you to edit the commit messages if you’ve squashed commits. Make any necessary changes to the commit messages, then save and close the editor again. The rebase will be finished, and your branch history will be updated.

Best Practices for Using Git Interactive Rebase

Here are some best practices to keep in mind when using Git’s interactive rebase feature:

• Perform rebases on local branches: Always perform an interactive rebase on branches that have not yet been pushed to a remote repository. Rewriting commit history on public branches can cause issues for others working on the same branch.
• Test thoroughly after rebasing: After performing a rebase, make sure to test your code to ensure nothing was broken during the process.
• Use rebase before pushing to remote: Before pushing your changes to a shared repository, use rebase to clean up your commit history and ensure that your commits are logically ordered.
• Communicate with your team: If you’re collaborating on a project, make sure everyone is aware of any rebases performed to avoid confusion or conflicts.

Conclusion

Interactive rebasing in Git is a powerful tool for cleaning up your commit history, improving collaboration, and keeping your Git repository organized. By following the steps outlined in this guide, you can confidently use git rebase -i to manage your commit history and ensure a cleaner, more understandable project history.

Remember to use interactive rebase responsibly, especially when working with shared branches, to avoid issues with others’ workflows. Whether you’re reordering commits, squashing them, or editing commit messages, Git interactive rebase gives you full control over your commit history.