exit EXPR
        Evaluates EXPR and exits immediately with that
        value.    Example:

             $ans = <STDIN>;
             exit 0 if $ans =~ /^[Xx]/;

        See also "die".  If EXPR is omitted, exits with 0
        status.  The only universally recognized values
        for EXPR are 0 for success and 1 for error; other
        values are subject to interpretation depending on
        the environment in which the Perl program is run-
        ning.  For example, exiting 69 (EX_UNAVAILABLE)
        from a sendmail incoming-mail filter will cause
        the mailer to return the item undelivered, but
        that's not true everywhere.

        Don't use "exit" to abort a subroutine if there's
        any chance that someone might want to trap what-
        ever error happened.  Use "die" instead, which can
        be trapped by an "eval".

        The exit() function does not always exit immedi-
        ately.  It calls any defined "END" routines first,
        but these "END" routines may not themselves abort
        the exit.  Likewise any object destructors that
        need to be called are called before the real exit.
        If this is a problem, you can call
        "POSIX:_exit($status)" to avoid END and destructor
        processing.  See perlmod for details.