#!/bin/sh

git filter-branch --commit-filter '
if [ "$GIT_COMMITTER_NAME" = "OLD_USERNAME" ];
then
  GIT_COMMITTER_NAME="NEW_USERNAME";
  GIT_AUTHOR_NAME="NEW_USERNAME";
  GIT_COMMITTER_EMAIL="EMAIL_NEW_USERNAME";
  GIT_AUTHOR_EMAIL="EMAIL_NEW_USERNAME";
  git commit-tree "$@";
else
  git commit-tree "$@";
fi' HEAD