/WAIT (default)
       /NOWAIT

    Controls whether EFI$CP waits until the subprocess is completed
    before allowing more EFI$CP commands to be entered. The /NOWAIT
    qualifier allows you to enter new EFI$CP commands while the
    specified subprocess is running. If you specify /NOWAIT, you
    should also use the /OUTPUT qualifier to direct the output stream
    to a file rather than to your terminal. Doing so prevents your
    terminal from being used by more than one process simultaneously.

    EFI$CP> SPAWN
    $ SHOW TIME
    $ LOGOUT
      Process DJONES_1 logged out at 25-APR-2003 16:59:17.37
    EFI$CP>