I've been working with hash for a while now, but there is something i really don't understand. 
my $hash = {};

do_something( $hash );
print Dumper( $hash );

sub do_something
{
    my $hash = shift;

    $hash = { a => 'alpha',
              b => 'beta',
            };

    print Dumper( $hash );
}

[download]
when exectuted: 
{
  'a' => 'alpha',
  'b' => 'beta'
}
{}

[download]
but if using: 
do_something_else( $hash );
print Dumper( $hash );

sub do_something_else
{
    my $hash = shift;

    $hash->{g} = 'gamma';
    $hash->{d} = 'delta';

    print Dumper( $hash );
}

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it shows: 
{
  'd' => 'delta',
  'g' => 'gamma'
}
{
  'd' => 'delta',
  'g' => 'gamma'
}

[download]
To me the initialization of $hash is the same in both subs, but apparently it is not. It's probably something very trivial, but i just miss it. Would you please explain why? TIA.

In reply to hash question by duyet

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