use strict;
my @B;
my $len = 4096;
my $str = '........'; #langer String
while (length($str)>$len) {
    my $e = substr($str, 0, $len);
    substr($str,0,$len) = '';
    push(@B, $e);
}
push (@B, $str) if length($str);

my $len = 4096;
my $stringLength = length($string);

my $count = int($stringLength/$len);
my $pattern = ("A$len " x $count) . " A*";
my @B = unpack($pattern, $stringLength);

#! /usr/bin/perl

my $string = 'Dies ist ein ganz langer Test';
my $length = 4;
my @array = $string =~ /(.{1,$length})/g;

print $_,"\n" for(@array);