Success: suffix("a.b",".b"). suffix("dead.letter",".letter"). suffix("top.pl",S). (gives S=".pl"). suffix("bugs",S). (gives S=""). suffix("../my.pl",S). (gives S=".pl"). suffix("../user/my.c",S). (gives S=".c"). suffix("/home/user/pl/.trace",S). (gives S=".trace"). Fail: suffix("file.pl",".c"). Error: suffix(F,S). (Error 4). suffix('file1.pl',S). (Error 5). suffix("file1.pl",'.pl'). (Error 5).