{
    use Getopt::Long;
    my %opt;
    GetOptions (
        \%opt,
        qw/ verbose! file:s debug+ help/
    ) || die sub { print <<END_OF_HELP;
$0: you blew it! Switches are as follows:
    --help | -h  this help screen
...
END_OF_HELP
    }
    sub debug   { exists $opt{debug} ? $opt{debug} : 0 }
    sub verbose { exists $opt{verbose} ? 1 : 0 }
    sub file    {
        if( not exists $opt{f} ) {
            ''
        }
        elsif( not defined $opt{f} ) {
            '/etc/passwd'
        }
        else {
            $opt{f}
        }
    }
}