    --port 3456 \
    <&- &
pid=$!

cleanup() {
    printf >&5 '\n'
    if [ "$(ps -q "${pid}" -o ppid=)" != "$$" ]; then
        printf >&5 \
            'Exiting. Server seems to have stopped (was pid %d).\n' "${pid}"
    else
        printf >&5 'Exiting. Also stop server (y/N)? '
        line=
        read -r line || printf >&5 '\n'
        if [ "${line-}" = y ] || [ "${line-}" = Y ]; then
            kill "${pid}"