VMS Help SHOW, LOGICAL, Qualifiers, /STRUCTURE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /STRUCTURE
       /NOSTRUCTURE (default)

    Controls whether the system displays the "family tree" of all
    accessible logical name tables. The display includes the two
    logical name directory tables (process and system) and all
    logical name tables cataloged in these directory tables. Any
    descendant logical name tables are shown under their parent
    tables.

    If you specify the /STRUCTURE qualifier, you cannot use any other
    qualifiers except /ACCESS_MODE, /FULL, and /OUTPUT.