use strict;
use warnings;
use Data::Dumper;

local $; = '#';

my %hash1;
$hash1{'Hello', 'World'} = 1;
$hash1{'Hello', 'Pluto'} = 2;
$hash1{'Goodbye', 'World'} = 3;
$hash1{'Goodbye', 'Pluto'} = 4;

my %hash2 = %hash1; # copy
$hash2{'Goodbye', 'Pluto'}++; # alter hash 2

print "$hash2{'Goodbye', 'Pluto'}\n";  # show that it is altered
print "$hash1{'Goodbye', 'Pluto'}\n";  # hash1 remains unaltered

# Let's see what's going on here...
print Dumper(\%hash1, \%hash2);