15.64.27  FLUSH 

     FLUSH [ON|OFF]
This  selects  automatic  flush  of plot data.  When automatic flushing of
data is on, plot data is displayed immediately after each interactive line
of  input.   When OFF plot data is only displayed after a FLUSH command or
when the plot buffer is  full.   Pause  is  normally  on  for  interactive
devices, and off for non interactive.