Strange VMS Error Messages

  xyz$ exit 2928
  %SYSTEM-W-FISH, my hovercraft is full of eels
  xyz$ exit 2930
  %SYSTEM-E-FISH, my hovercraft is full of eels
  xyz$ exit 2930
  %SYSTEM-F-FISH, my hovercraft is full of eels
  xyz$ exit 2934
  %SYSTEM-?-FISH, my hovercraft is full of eels
  xyz$

sample program to generate each message as a warning

    set control=(t,y)
    count = 0
  main:
    write sys$output count,", ",f$message(count)
    count = count + 8
    goto main