copy(File1, File2) :- 
          %seeing(Old1),      /* save for later */ 
          %telling(Old2),     /* save for later */
          see(File1),        /* open this file */
          tell(File2), 
          repeat, 
          get_char(Data),       /* read from File */ 
          process(Data),    
          seen,             /* close File */
          told, 
          % see(Old1),         /*  previous read source */ 
          % tell(Old2),         /* previous write source */
          !.                /* stop now */ 
 
process(end_of_file) :- !. 
process(Data) :-  put_char(Data), fail.