# define option names and defaults
our $UNIQUE_OPT         = q/unique/;
our $FORCE_OPT          = q/force/;
our $VERBOSE_OPT        = q/verbose/;
our $OUTPUT_EXT_OPT     = q/ext/;

# create option specs for Getopt
my @option_config = qw( $UNIQUE_OPT
                        $FORCE_OPT
                        $VERBOSE_OPT
                        $OUTPUT_EXT_OPT=s
                      );
                      
# create option hash for Getopt
my(%option, %option_config);
foreach my $option_config ( @option_config ) 
{
	# copy $option_config to $option_name, keep only name of option
	( my $option_name = $option_config ) =~ s/\W.*$//;
	# save a reference to the %option value in %option_config hash
	$option_config{$option_config} = \$option{$option_name};
}
# process options
GetOptions %option_config or usage();

if ( $option{$UNIQUE_OPT} and $option{$FORCE_OPT} )
{
    die "-$UNIQUE_OPT and -$FORCE_OPT are mutually exclusive." 
      . " See $SCRIPT_NAME -help for syntax.";
}