#!/usr/bin/perl -w

use strict;
use Data::Dumper;

my %hash;

print Dumper(\%hash);

$hash{one}->{key1} = 'value1';
$hash{one}->{key2} = 'value2';

print Dumper(\%hash);

##</code><code>##

$hash{one}->{key1} = 'value1';
$hash{one}{key1} = 'value1';