AT-INVALID(1) General Commands Manual AT-INVALID(1) NNAAMMEE AAtt--iinnvvaalliidd - handling of an invalid AT&T UNIX argument DDEESSCCRRIIPPTTIIOONN no argument: AT&T UNIX valid argument: Version 7 AT&T UNIX invalid argument: AT&T UNIX murks bboolldd end of file OpenBSD July 4, 2017 OpenBSD