VMS Help SPAWN, Example  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  $ RUN MYPROG
        .
        .
        .

  $ <Ctrl/Y>
  $ SPAWN MAIL
  %DCL-S-SPAWNED, process SKONETSKI_1 spawned
  %DCL-S-ATTACHED, terminal now attached to process SKONETSKI_1
  MAIL> READ
     .
     .
     .
  MAIL> EXIT
  %DCL-S-RETURNED, control returned to process SKONETSKI
  $ CONTINUE

      The SPAWN command in this example allows you to enter the
      OpenVMS Mail utility (MAIL) without terminating the currently
      running program. After you exit from Mail, control is returned
      to the parent process.