By using this method, a user can not only interact with the external program from within the editor environment, but can also create {TAIL ~ an editor file} that stores {HEAD ~ a listing} of the input and output provided to the external program 
By using this method , a user can not only interact with the external program from within the editor environment , but can also create { TAIL ~ an editor file } that stores { HEAD ~ a listing } of the input and output provided to the external program
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 TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH