I suggest you use strict; because you would have received an error instead of nothing.

This:

  foreach (sort keys %hashref) {
    print "$_ : $hashref{$_}\n";
  }
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Should be replace by this:

  foreach (sort keys %{$hashref}) {
    print "$_ : ", $hashref->{$_}, "\n";
  }
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I was using a HashRef not a Hash, $hashref is not the same variable as %hashref, so if you loop through %hashref, of course you get nothing because it is an empty variable. Using strict would have prevent you from doing this. I hope this helps!