/MESSAGES=(option[,...])

    Positional qualifier.

    Specifies the destination of all DSR error messages. To indicate
    a specific destination, use one or both of the following options:

    OUTPUT     Messages are sent to the output .MEM file.
    USER       Messages are displayed on the terminal (SYS$ERROR).

    If you specify both options, separate them with commas and
    enclose the list in parentheses.

    The default, /MESSAGES=(OUTPUT,USER), sends messages to the
    output .MEM file and displays them on the terminal.