my %options;
my @required = qw(table id_field);

GetOptions
  ( \%options,
   'table=s',
   'id_field=s',
   'state_field=s',
   'zip_field=s',
   'dob_field=s',
   'help|?',
   'man'
) or die pod2usage(2); # dies if an unlisted option is given

# if an option isn't specified, it isn't set in the hash so 
# we look for the ones we want and make certain they're there
die pod2usage(2) if grep(!exists $options{$_},@required);