foreach (@geteilt)
{ if ($a < @teil+1) {$a +=2}
}

print $geteilt[$a]." ";

#!/usr/bin/perl

use strict;
use warnings;

my $string = 'acacagagatcgctagatcgatcgatcgat';
my @values = $string =~ /(.{3})/g;

print $_,"\n" for @values;