exit EXPR
    exit    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
            running. 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 whatever error happened. Use
            "die" instead, which can be trapped by an "eval".

            The exit() function does not always exit immediately. 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. "END"
            routines and destructors can change the exit status by modifying
            $?. If this is a problem, you can call "POSIX::_exit($status)"
            to avoid END and destructor processing. See perlmod for details.

            Portability issues: "exit" in perlport.