Git Author Email and Name Batch Modification Script

git_modify.sh

#!/bin/bash

# ===============================================================================
# Git Author Email and Name Batch Modification Script
# ===============================================================================
#
# DESCRIPTION:
#   This script allows you to retroactively modify the author email and name
#   for a range of Git commits. It uses interactive rebase to systematically
#   update commit author information while preserving original commit dates
#   and other metadata.
#
# USE CASES:
#   - Correcting author information after accidental commits with wrong email
#   - Updating author details for privacy or organizational requirements
#   - Standardizing author information across a project's history
#   - Fixing commits made with incorrect Git configuration
#
# PREREQUISITES:
#   - Git repository with commit history
#   - No uncommitted changes in the working directory
#   - Backup of your repository recommended before running
#
# USAGE:
#   1. Edit the configuration variables below (NEW_EMAIL, NEW_NAME, START_COMMIT)
#   2. Ensure your working directory is clean
#   3. Run the script: bash modify_email.sh
#   4. In the interactive rebase editor, mark commits as 'edit' and save
#   5. The script will automatically process each commit
#
# WARNING:
#   This script modifies Git history and should be used with caution.
#   Force pushing may be required if the branch has been shared.
#   Always backup your repository before running this script.
#
# ===============================================================================

# Configuration Variables
NEW_EMAIL="[email protected]"
NEW_NAME="Foo Bar"

# Starting commit hash (from which commit to start modifying)
START_COMMIT="c4a77a5"

# Get all commits from the specified commit to HEAD
commits=$(git rev-list --reverse $START_COMMIT..HEAD)

echo $commits

# Start interactive rebase
# In the editor, mark each commit as 'edit', then save and exit
git rebase -i $START_COMMIT

# Iterate through each commit for modification
for commit in $commits; do
  # Get the original author and time information of the commit
  AUTHOR=$(git show -s --format='%an <%ae>' $commit)
  DATE=$(git show -s --format='%ad' --date=iso $commit)

  # Execute modification operation on each commit
  GIT_COMMITTER_DATE="$DATE" git commit --amend --no-edit --author="$AUTHOR" --date="$DATE" --author="$NEW_NAME <$NEW_EMAIL>"

  # Manually execute git rebase --continue
  git rebase --continue
done