#!/usr/bin/perl
use warnings;
use strict;
use diagnostics;
my $Dna1 = "AACAGCACGGCAACGCTGTGCCTTGGGCACCATGCAGTACCAAACGGAACGATAGTGAAAACAATCACGA\n";
          
while ($Dna1 =~ /(C[AG]G)/g) {
      my $endposition = pos($Dna1) + 1;
      print "Pattern C[AG]G matched $1 ending at $endposition\n";
}

##</code><code>##

Pattern C[AG]G matched CAG ending at 6
Pattern C[AG]G matched CGG ending at 11
Pattern C[AG]G matched CAG ending at 38
Pattern C[AG]G matched CGG ending at 48