/WAIT (default)
       /NOWAIT

    Requires that you wait for the subprocess to terminate before
    you enter another DCL command. The /NOWAIT qualifier allows you
    to enter new commands while the subprocess is running. (Use the
    /OUTPUT qualifier with the /NOWAIT qualifier to avoid
    displaying both parent and subprocess output on the terminal
    simultaneously.)

    Note that specifying the /NOWAIT qualifier causes both input
    and output to be shared with the parent process. If the input
    device is a terminal, control characters, such as CTRL/T or CTRL/Y,
    also affect all subprocesses sharing the input device. The
    CTRL/Y control character, for example, interrupts all such
    subprocesses. This problem may be avoided by specifying /INPUT=NL:.