reset_committer.sh

git filter-branch --commit-filter '
        if [ "$GIT_COMMITTER_NAME" = "OLD NAME" ];
        then
                GIT_COMMITTER_NAME="nevermoe";
                GIT_AUTHOR_NAME="nevermoe@users.noreply.github.com";
                GIT_COMMITTER_EMAIL="nevermoe@users.noreply.github.com";
                GIT_AUTHOR_EMAIL="nevermoe@users.noreply.github.com";
                git commit-tree "$@";
        else
                git commit-tree "$@";
        fi' HEAD

# from: http://stackoverflow.com/a/870367/36850