VMS Help CMS, RESERVE, Qualifiers, /OUTPUT[=file-specification]  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Directs CMS to write output to the specified file. If you omit the
    /OUTPUT qualifier (or if you specify /OUTPUT but do not provide a
    file specification), CMS creates a file with the same name as the
    element in your default directory.

    If you reserve more than one element (by specifying wildcards or a
    group name for the element expression parameter), and you do not
    specify wildcards in the output file specification, CMS creates
    successive versions of the file indicated by /OUTPUT.