use Getopt::Std;
getopts (":s:n:",\%args);
if (defined $args{s}){
          $string = $args{n};
}
if (defined $args{n}) {
          $number = $args{n};
}
if (!defined $args{s} or !defined $args{s}) {
          print "Usage: perl $0 -s string -n number\n";
          exit;
}
print "This is a string = $string \nThis is a number = $number\n";