#! /usr/local/bin/perl
use strict;
use warnings;
use Data::Dumper;

my $input = "1234567890abcdefghij0987654321ABCDEFGHIJlmnop";

chomp $input;

# A  "A text (ASCII) string, will be space padded."

my @chunks = unpack("(A10)*", $input);

print Dumper(\@chunks);

__END__

$VAR1 = [
          '1234567890',
          'abcdefghij',
          '0987654321',
          'ABCDEFGHIJ',
          'lmnop'
        ];