/OUTPUT=filespec

    Specifies the name of the file to which the command procedure
    output is written. By default, the output is written to the
    current SYS$OUTPUT device. The default output file type is
    .LIS. The asterisk (*)  and the percent sign (%) wildcard
    characters are not allowed in the output file specification.
    System responses and error messages are written to SYS$COMMAND
    as well as to the specified file. The /OUTPUT qualifier must
    immediately follow the file specification of the command
    procedure; otherwise, the qualifier is interpreted as a parameter
    to pass to the command procedure.

    You can also redefine SYS$OUTPUT to redirect the output from a
    command procedure. If you place the following command as the
    first line in a command procedure, output will be directed to the
    file you specify:

    $ DEFINE SYS$OUTPUT filespec

    When the procedure exits, SYS$OUTPUT will be restored to its
    original equivalence string. This produces the same result
    as using the /OUTPUT qualifier when you execute the command
    procedure.