Rewrite git commiter information based on mapping

rewrite_git_history.sh

#!/bin/env bash

# This script and mailmapping file should be on the same level as the directory
# containing the repo
#
# mailmapping file should have the following format:
# name surname [email protected] [email protected]
#
# List of commiter names emails can be obtained with:
# git shortlog -sne
# this information can be used to craft the mailmapping file

repo_name="repo-dir-name-goes-here"
input_file="../mailmapping"

cd "$repo_name"
while read name surname email old_email
do
  export OLD_EMAIL=$old_email
  export CORRECT_EMAIL=$email
  export CORRECT_NAME=$name
  export CORRECT_SURNAME=$surname
  git filter-branch -f --env-filter '
  if test "$GIT_COMMITTER_EMAIL" = "$OLD_EMAIL"
  then
      export GIT_COMMITTER_NAME="$CORRECT_NAME $CORRECT_SURNAME"
      export GIT_COMMITTER_EMAIL="$CORRECT_EMAIL"
  fi
  if test "$GIT_AUTHOR_EMAIL" = "$OLD_EMAIL"
  then
      export GIT_AUTHOR_NAME="$CORRECT_NAME $CORRECT_SURNAME"
      export GIT_AUTHOR_EMAIL="$CORRECT_EMAIL"
  fi
  ' --tag-name-filter cat -- --all
done < "$input_file"