my %month = ( 'JAN' => 1, 'FEB' => 2, 'MAR' => 3, 'APR' => 4, 'MAY' => 5, 'JUN' => 6, 'JUL' => 7, 'AUG' => 8, 'SEP' => 9, 'OCT' => 10, 'NOV' => 11, 'DEC' => 12);
$col[5] = 'MAY052010';
($c{month}, $c{day}, $c{year}) = $col[5] =~ /(.{3})(\d{2})(\d{4})/;
$c{month} = $month{$c{month}} #or...