gistfile1.txt

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