#!perl -w
use strict;
use Data::Dumper;
my @hashes;
for (1..2) {
    push @hashes, { foo => 'bar' };
};
$hashes[0]->{baz} = 1;
print Dumper $hashes[1]; # { foo => 'bar' }

##</code><code>##

<c>
#!perl -w
use strict;
use Data::Dumper;
my @hashes;
my $constant_hash = { foo => 'bar' };
for (1..2) {
    push @hashes, $constant_hash;
};
$hashes[0]->{baz} = 1;
print Dumper $hashes[1]; # { foo => 'bar', baz => 1 }