/sys$common/syshlp/helplib.hlb SHOW, ERROR, Qualifiers, /OUTPUT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /OUTPUT[=filespec]
       /OUTPUT=SYS$OUTPUT (default)

    Specifies the file to which the display is written. By default,
    the display is written to the current SYS$OUTPUT device.

    If you enter the /OUTPUT qualifier with a partial file
    specification (for example, specifying only a directory), SHOW
    is the default file name and .LIS the default file type. The
    asterisk (*)  and the percent sign (%) wildcard characters are
    not allowed in the file specification.

    If you enter the /NOOUTPUT qualifier, output is suppressed.