https://twitter.com/ttjee/status/334706637111713792

dna-sequence-count.pl

#!/usr/bin/env perl

use 5.010;
use strict;
use warnings;

print "Enter your DNA sequence: ";

my $input = <STDIN>;
chomp $input;

my @groups = $input =~ m/(.{1,3})/g;

say "count of groups: ", scalar(@groups);

my $count = 0;
for my $group (@groups) {
    ++$count;
    say "group[$count]: $group";
}

__DATA__

How to Run?

$ perl  dna-sequence-count.pl
Enter your DNA sequence: ATGCATGCATGCATGCATGC
count of groups: 7
group[1]: ATG
group[2]: CAT
group[3]: GCA
group[4]: TGC
group[5]: ATG
group[6]: CAT
group[7]: GC