Re: char substitution without regexes

[jwkrahn]

( my $new = reverse $string ) =~ tr/atgc/tacg/;
print "$new\n";

Update: Also if you want to remove any non a, t, c or g characters:

( my $new = reverse $string ) =~ tr/atgc\0-\277/tacg/d;
print "$new\n";