How to Change Commit Message in Git?

Changing a commit message in Git can be done in a few different ways, depending on whether the commit is the most recent one or an earlier commit. Here's an article on how to change a commit message in Git, covering scenarios both before and after the commit has been pushed to a remote repository.

These are the following topics that we are going to discuss:

Changing the Most Recent Commit Message (Not Pushed Yet)

If the commit only exists in your local repository and has not been pushed to a remote repository, you can amend the commit message using the following command:

git commit --amend

This command opens your text editor, allowing you to edit the commit message. Make the necessary changes, save the commit, and close the editor.

Note: Ensure that you don’t have any uncommitted changes staged, as they will also be included in the amended commit.

Changing a Commit Message That Has Already Been Pushed

If you’ve already pushed the commit to a remote branch, you'll need to force-push the amended commit. Force pushing can overwrite the history on the remote repository, so use it with caution.

• Amend the commit message locally as described above.
• Force push the amended commit to the remote branch using:

   git push <remote> <branch> --force

Note: Replace `<remote>` with the remote repository name (e.g., `origin`) and `<branch>` with the branch name

Warning: Force-pushing rewrites the remote branch with your local state, which can cause data loss for collaborators who have already pulled the previous version of the commit.

Interactive Rebase (For Older or Multiple Commits)

If you need to update messages for multiple commits or older commits, use interactive rebase:

• Start an interactive rebase:

 git rebase -i HEAD~n   

Note: Replace `n` with the number of commits you want to go back

• In the interactive editor, choose the commit(s) you want to edit by replacing `pick` with `reword` (or `edit` for more complex changes).
• Update the commit messages as necessary and save the changes.
• Complete the rebase process by following the prompts. If you used `edit`, you will need to re-commit the changes.

Important: Be cautious when rewriting shared commit history, especially if other collaborators are working on the same branch.

Practical Example

Let's assume you want to change the message of the most recent commit:

• Run:

   git commit --amend

• Edit the commit message in the editor that opens.
• Save and close the editor.
• If the commit was already pushed, force push it to the remote repository:

   git push origin main --force

For changing an older commit, let's say the last 3 commit:

• Run:

   git rebase -i HEAD~3

• In the editor, change `pick` to `reword` for the commit(s) you want to change.
• Save and close the editor.
• Edit the commit messages as prompted.
• Force push the rebased commits:

   git push origin main --force

By following these steps, you can effectively manage and correct commit messages in your Git repository. Always communicate with your team when rewriting history to avoid conflicts and data loss.