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

   /WAIT (D)
   /NOWAIT

   Controls whether the system waits until the subprocess is
   completed before enabling more commands to be issued to the parent
   process. The /NOWAIT qualifier enables you to enter more commands
   while the specified subprocess is running. When you specify
   /NOWAIT, you should also specify /OUTPUT to direct output to a
   file (rather than to the screen). This prevents the terminal from
   being used by both processes simultaneously.