Daniele Cammarata

Sometimes, you may need to change the author information of previous commits in your Git repository. Whether you want to correct a mistake, update your email address, or reassign commits to another author, Git provides powerful tools to help you rewrite history. In this blog post, we’ll walk you through the steps to change the author of commits in your Git history.

Prerequisites

Before you begin, make sure you have the following:

Git installed on your system.
A local copy of the Git repository where you want to change the commit author.

Important Considerations

Changing commit history can have significant consequences, especially if the repository is shared with others or has been pushed to a remote server. When you rewrite history, it creates new commit hashes, which can cause conflicts for other collaborators. It’s best to perform these changes on branches that have not yet been shared or to coordinate with your team before proceeding.

Changing the Author of the Most Recent Commit

If you only need to change the author of the most recent commit, you can use the --amend option with git commit. Here’s how:

Set the desired author information:

git config user.name "New Author Name"
git config user.email "newauthor@example.com"

Amend the most recent commit:

git commit --amend --no-edit --reset-author

Push the changes to the remote repository:
```
git push --force
```

Changing the Author of Multiple Commits

To change the author of multiple commits, you’ll need to use an interactive rebase. This allows you to edit each commit’s metadata, including the author information.

Start an interactive rebase:
```
git rebase -i HEAD~n
```
Replace n with the number of commits you want to rebase. For example, HEAD~5 will start an interactive rebase for the last five commits.
Mark the commits for editing:

In the text editor that opens, change pick to edit for each commit you want to change:
```
edit <commit-hash> Commit message
edit <commit-hash> Commit message
```
Edit each commit:

For each commit marked for editing, Git will pause and allow you to change the author information:
```
git commit --amend --author="New Author Name <newauthor@example.com>"
git rebase --continue
```
Repeat the process:

Repeat the amend and continue steps for each commit you marked for editing.
Push the rewritten history:
```
git push --force
```

Changing the Author of All Commits

If you need to change the author of all commits in a repository, you can use a script to automate the process. Here’s an example using Git’s filter-branch command:

Create a script:

#!/bin/bash
git filter-branch --env-filter '
OLD_EMAIL="oldemail@example.com"
CORRECT_NAME="New Author Name"
CORRECT_EMAIL="newauthor@example.com"

if [ "$GIT_COMMITTER_EMAIL" = "$OLD_EMAIL" ]
then
    export GIT_COMMITTER_NAME="$CORRECT_NAME"
    export GIT_COMMITTER_EMAIL="$CORRECT_EMAIL"
fi
if [ "$GIT_AUTHOR_EMAIL" = "$OLD_EMAIL" ]
then
    export GIT_AUTHOR_NAME="$CORRECT_NAME"
    export GIT_AUTHOR_EMAIL="$CORRECT_EMAIL"
fi
' --tag-name-filter cat -- --branches --tags

Make the script executable:
```
chmod +x change-author.sh
```
Run the script:
```
./change-author.sh
```

Push the changes to the remote repository:

git push --force --tags origin 'refs/heads/*'

Conclusion