in reply to Common elements of a hash of hashes

Here is the idea for an algorithm for that:
  1. count all keys into a new hash
  2. Delete all those entries from the new hash where the count is equal to the number of "eltX" elements
  3. What remains in the new hash are the keys that are to be delete
$\=~s;s*.*;q^|D9JYJ^^qq^\//\\\///^;ex;print

In Section Seekers of Perl Wisdom