Win8 Strawberry 5.30.3.1 (64)  Sun 04/25/2021 15:11:49
C:\@Work\Perl\monks
>perl

use 5.014;  # /r modifier for tr///anslation & s///ubstitution

use strict;
use warnings;

my $s = 'ACTGTTCCAAGG';
print "'$s' \n";

$s = reverse $s =~ tr/ATCG/TAGC/r;
print "'$s' \n";

^Z
'ACTGTTCCAAGG'
'CCTTGGAACAGT'