How to Use the Command `git reauthor` (with Examples)
The git reauthor command is a powerful tool for developers who need to modify author information in Git commit history. This command is part of the git-extras package, which provides various supplementary Git utilities. git reauthor is specifically used to change details about an author’s identity in the repository’s commit history. Because it alters the Git history, subsequent pushes require the --force option to overwrite the remote repository. Here, we’ll discuss various scenarios in which git reauthor can be utilized, demonstrated through practical examples.
Use Case 1: Change an Author’s Email and Name Across the Whole Git Repository
Code:
git reauthor --old-email old@example.com --correct-email new@example.com --correct-name "name"
Motivation:
This use case is particularly useful when an individual has changed their email address or has legally changed their name. For instance, if Jane Doe has updated her professional email from jane.doe@oldmail.com to jane.doe@newmail.com, she would want to reflect this change across all her contributions in the repository for consistency and accuracy. This ensures that tracking future contributions or collaboration involving her previous email will not cause confusion.
Explanation:
--old-email old@example.com: This argument specifies the current email address associated with the commits that need updating. It’s essential to know the exact string of the email you want to change.--correct-email new@example.com: This is the new email address that will replace the old one in all the commits.--correct-name "name": This defines the new author name to set for the commits, altering it as needed to reflect any personal or professional name changes.
Example Output:
After executing the command, every commit that was originally authored with old@example.com will now display new@example.com and the updated author name, “name”. Running git log will confirm these changes.
Use Case 2: Change the Email and Name to the Ones Defined in the Git Config
Code:
git reauthor --old-email old@example.com --use-config
Motivation:
This scenario is advantageous when the local Git configuration—set through git config user.name and git config user.email—is the most current and preferred identity of the user. Developers may use this option to swiftly update historical commits to align with their latest Git configuration, promoting consistency between their local setup and the commit history.
Explanation:
--old-email old@example.com: Identifies the email address currently associated with the commits that should be changed.--use-config: This option fetches the author name and email directly from the current Git configuration settings, automatically applying them in place of the specified old email. No manual input is needed for the new name and email.
Example Output:
The output reveals that all commits initially associated with old@example.com are now attributed to the name and email defined in the user’s Git config. Use git log to verify the update.
Use Case 3: Change the Email and Name of All Commits, Regardless of Their Original Author
Code:
git reauthor --all --correct-email name@example.com --correct-name name
Motivation:
This particular scenario is useful for projects undergoing a complete rebranding or legal changes that necessitate altering all commit author information en masse. In situations such as a company transitioning to a new corporate identity, this command allows developers to uniformly change commit author info without concern for the original author details.
Explanation:
--all: This argument targets all commits in the repository, overriding previous author email and name data.--correct-email name@example.com: This provides the new email address to be used universally across the project’s commit history.--correct-name name: This establishes a new universal author name for all commits in the repository.
Example Output:
The result of this command is a completely revised Git history where each commit is authored by the specified new name and email. Checking with git log will illustrate this uniform change.
Conclusion:
The git reauthor command offers a flexible approach to managing and correcting author information within Git commit history. Whether dealing with personal identity changes, syncing with Git config preferences, or broadly applying new author details to every commit, these examples provide valuable guidance for utilizing git reauthor effectively. Remember, due to the nature of Git history rewriting, always proceed carefully and ensure proper backups are in place.
