I would be inclined to cache results for as long as I deemed necessary, and use the Cache::FileCache module to retrieve that large hash we have.

  use Cache::FileCache;


  my $cache = new Cache::FileCache( );
  my $hash = $cache->get( $assigned_hash_name );
  my %hash = %{$hash};
[download]

To edit the hash, all we would have to do is reset the cache to the new hash(ref), and to delete it all we have to do is:  $cache->Purge( )

We can then grep using Zaxo's code, or we could devise our own.

Notice: Code has not been tried, and is liable to break down at any time, and is probably not the best course of action.

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Gyan Kapur
gyan.kapur@rhhllp.com