VMS Help DTM, SPAWN, Command Qualifiers, /CLI  *Conan The Librarian (sorry for the slow response - running on an old VAX)

   /CLI[=cli]
   /NOCLI

   Specifies an alternate command language interpreter (CLI) for the
   subprocess to use. The default is the CLI the parent process uses.

   The CLI you specify must be located in SYS$SYSTEM and have the
   file type .EXE.