(From card games in which certain cards, often the joker, can act as any other card) A special character or character sequence which matches any character in a string comparison, like ellipsis ("...") in ordinary written text.In Unix filenames ' ?'matches any single character and ' *'matches any zero or more characters.In {regular expressions}, ' .'matches any one character and "[...]" matches any one of the enclosed characters.See also Backus-Naur Form.(1997-07-16)