It's really a long time since I worked with this, but as far as I can remember, this should work:

clear
cPrinter = getprinter()
if !empty(cPrinter)
  set printer to dump.dmp
  set printer on
  eject
  set printer to name (cPrinter)
  erase dump.dmp
  ???chr(27)+chr(77)+chr(27)+chr(112)+'0'
  ? "Hello world online"
  eject
  set printer off
  set printer to
endif

By the way, WHY do you need to do it this way? As mentioned, I have not done it this way in a lot of years, simply because there are other, better ways to do things.

>This is the updated code. It still causes a form feed in between run.
>
>

>clear
>set printer to dump.dmp
>set printer on
>?
>eject
>set printer off
>set printer to
>
>cPrinter = getprinter()
>if !empty(cPrinter)
>	set printer to name (cPrinter)
>	set printer on
>         ???chr(27)+chr(77)+chr(27)+chr(112)+'0'
>	? "Hello world online"
>	eject
>	set printer off
>	set printer to
>endif
>