my @dirs = qw (
/usr/local/bin/
/var/tmp/somefile
/
/home/foo/bar
);

foreach ( @dirs ) {
    my @dir;
    my $lastdir;

    if ( /^\/$/ ) {
        $lastdir = "/";
        print "$lastdir\n";
        next;
    }

    if ( /\/$/ ) {
        chop;
    }

    @dir = split('/');
    $lastdir = pop(@dir);
    print "$lastdir\n";
}