use Getopt::Std;

my %opts;
die "Usage: $0 -a file | -s state | -l\n".
    "-a adds to database (or create), -s lists state  -l lists whole DB\n"
    if (!getopts("a:s:l", \%opts) || @ARGV !=0 || keys %opts !=1; 
    
Add()         if $opts{a};
ListState()   if $opts{s};
ListAll()     if $opts{l};

sub ListState
{
   ...use $opts{s} here, the state name....
}