/OUTPUT=filespec

    Identifies the output file to which the results of the SPAWN
    operation are written. If you omit the /OUTPUT qualifier, output
    is written by default to the current SYS$OUTPUT device. Whenever
    you use the /NOWAIT qualifier, you should also use the /OUTPUT
    qualifier to specify a new output destination. Doing so prevents
    output from being displayed on your terminal while you are
    entering