#!/usr/bin/env perl

use strict;
use warnings;

use Data::Dumper;

my @MainArray;

while (<DATA>) {
    chomp;
    push @MainArray, [ split // ];
}

print Dumper \@MainArray;
 
__DATA__
Hello
my
name
is
Jack

##</code><code>##

$ pm_file_chars_to_AoA.pl
$VAR1 = [
          [
            'H',
            'e',
            'l',
            'l',
            'o'
          ],
          [
            'm',
            'y'
          ],
          [
            'n',
            'a',
            'm',
            'e'
          ],
          [
            'i',
            's'
          ],
          [
            'J',
            'a',
            'c',
            'k'
          ]
        ];