Kinda sorta not really. It all depends on whether what you're modifying is the stuff in the hash you copied or in child hashes. Let's say you have: 
my %hash = (
    key1 => {
        a => 1,
        b => 2,
    },
    key2 => 'blah'
);

my %hash1 = %{ $hash{key1} };

$hash1{a} = 3;    # This change persists
$hash1{c} = 5;    # This change does NOT persist

[download]
It all depends, doesn't it? :-) (And also why objects should encapsulate this crap.)

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In reply to Re3: Getting a branch of a nested hash by dragonchild
in thread Getting a branch of a nested hash by legLess

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