$ cat HoH.pl 
#!/usr/bin/perl -w
use strict;
use Data::Dumper;

our $HoH = do 'hash';
print Dumper($HoH);

$ cat hash
{
         'HASH_1' => {
                item_a => "abc",
                item_b => "123",
                item_c => "blue",
        },
        'HASH_2' => {
                item_a => "xyz",
                item_b => "789",
                item_c => "white",
        },
        'HASH_3' => {
                item_a => "ijk",
                item_b => "3.14",
                item_c => "yellow",
        }
}

$ ./HoH.pl 
$VAR1 = {
          'HASH_3' => {
                        'item_b' => '3.14',
                        'item_c' => 'yellow',
                        'item_a' => 'ijk'
                      },
          'HASH_2' => {
                        'item_b' => '789',
                        'item_c' => 'white',
                        'item_a' => 'xyz'
                      },
          'HASH_1' => {
                        'item_b' => '123',
                        'item_c' => 'blue',
                        'item_a' => 'abc'
                      }
        };