use CGI qw/:standard/;
use CGI::Cookie;

#...

my %cookies = fetch CGI::Cookie;

#...

$rows = $cookies{'rows'}
  ? ( param( 'rows' ) ? param( 'rows' ) : $cookies{'rows'}->value )
  : ( param( 'rows' ) and param( 'rows' ) =~ /^\d{1,2}$/ ? param( 'rows' ) : 5);

#...

my $rowscookie = new CGI::Cookie(  -name => 'rows',
                                  -value => $rows,
                                -expires => '+3M',
                                );

#...

print header(-cookie=>[$rowscookie,$colscookie]);

#...