Git: Changing author name or email for old commits in a git repo. Extracted from: http://stackoverflow.com/questions/750172/how-do-i-change-the-author-of-a-commit-in-git

edit-commit-author.sh

git filter-branch --commit-filter '
        if [ "$GIT_COMMITTER_NAME" = "<Old Name>" ];
        then
                GIT_COMMITTER_NAME="<New Name>";
                GIT_AUTHOR_NAME="<New Name>";
                GIT_COMMITTER_EMAIL="<New Email>";
                GIT_AUTHOR_EMAIL="<New Email>";
                git commit-tree "$@";
        else
                git commit-tree "$@";
        fi' HEAD