💬 Changing Git Config for Previous Commits🚚

Sometimes, you need to modify the author's name or email address for earlier commits. This might happen if you use the wrong email address, or perhaps you want to update your identity for privacy or other reasons. Fortunately, Git allows you to easily change the author name and email for previous commits using the filter-branch command.

The filter-branch command rewrites Git history by applying a filter to each commit. In this article, we’ll walk through how to change the author name and email for previous commits.

To Update the Author and Email for Specific Commits:

If you need to change the author and email for specific commits (e.g., replacing one old email with a new one), you can use the following command in your Git Bash shell:

git filter-branch --commit-filter '
  if [ "$GIT_AUTHOR_EMAIL" = "oldEmail.com" ];
  then
    GIT_AUTHOR_NAME="newAuthorName";
    GIT_AUTHOR_EMAIL="newAuthorEmail.com"; 
    git commit-tree "$@";
  else
    git commit-tree "$@";
  fi
' HEAD

To Update the Author and Email for All Commits:

If your goal is to replace the author name and email for every commit in the repository with a specific author name and email, you can use this command:

git filter-branch --commit-filter '
  GIT_AUTHOR_NAME="newAuthor Name"; 
  GIT_AUTHOR_EMAIL="newAuthorEmail.com";
  GIT_COMMITTER_NAME="$GIT_AUTHOR_NAME";
  GIT_COMMITTER_EMAIL="$GIT_AUTHOR_EMAIL";
  git commit-tree "$@";
' -- --all

Important Notes:

1. These commands should be executed in your Git Bash shell, which is available if you're using Git for Windows. Make sure you're in the root directory of your Git repository when running the command.
2. If you've already pushed commits to a remote repository, you'll need to force-push the changes to update the remote history:

git push --force --tags

Force-pushing rewrites the commit history. It can disrupt the work of other collaborators, so make sure you communicate with your team before doing so. It's often a good idea to only perform this operation on repositories that are not publicly available or on those where you are the only contributor.

By using these git filter-branch commands, you can effectively change the author name and email for past commits, whether for specific commits or all commits in your repository.