$ perl -le '$alpha = "abcdefghijklmnopqrstuvwxyz";
            $str = "This is a String";
            print grep { ($_) }
            map { 1 + index($alpha, $_), "\n" }
            split //,lc($str)'

__output__
20
8
9
19

9
19

1

19
20
18
9
14
7