{TAIL ~ The method} involves passing editor input to {HEAD ~ the external program}, wherein the external program evaluates the input, produces either lines of output or zero lines of output, and transmits the output back to the editor 
{ TAIL ~ The method } involves passing editor input to { HEAD ~ the external program } , wherein the external program evaluates the input , produces either lines of output or zero lines of output , and transmits the output back to the editor
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH