With those nits out of the way, here are a few workable strategies.

The most general is to generate a hash, by key, of which subhashes have that key. For instance (all code is untested):

my %with_key;
foreach my $first_key (keys %all_files) {
  foreach my $second key (keys %{$all_files{$first_key}}) {
    push @{$with_key{$second_key}}, $first_key;
  }
}
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A second strategy is to say that it makes no sense to search the entire data structure to produce a complex new data structure that you have to search again. So if what you need is simple, then you could walk all of the data and generate the totals that you need in one pass:

my %total;
foreach my $subhash (values %all_files) {
  foreach my $key (keys %$subhash) {
    $total{$key} += $subhash->{$key};
  }
}
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I don't know exactly what you want to do, but either of these strategies will work.

UPDATE: I added an arrow in the second code snippet to dereference $subhash. This is the kind of typo that strict.pm catches for me when I try to run code...

thank you for your post! however trying to implement your second solution I am failing to see how this is adding the common keys within my HoH? I am using strict and warnings, the code above was just a snip from the entire program. Here is the code I threw in and played with.

  my %total;
  my %subhash;
  foreach my $subhash (values %all_files) {
    foreach my $key (keys %$subhash) {
      my $junk = $total{$key} + $subhash{$key};
      print "$junk\n";
    }
}
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the results of adding this to total the values for the common keys always results in '0'? I have also tried creating a AoH instead but still have problems getting the correct accumalation... Here is the code for that.

  for my $i ( 0 .. $#AoH ) {
    for my $role (sort keys %{ $AoH[$i] } ) {
      my $tcount = $AoH[$i]{$role} + $AoH[$i]{$role};
      print "$role=$tcount\n";
    }
  }
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either way what I would like to accomplish is for each common key within the hash (either below the main array or main hash) accumalate the value for common keys...? maybe I'm just brain dead at this point from looking at it too long... thanks...

I'm sorry, that was due to a typo on my part (I did warn that the code was untested).

You need to write $subhash->{$key} and not $subhash{$key} because you need to dereference the scalar $subhash, not access %subhash. (As I note in my update, strict.pm catches this kind of bug for you.)

If this fix confuses you, then I'd highly recommend reading references quick reference.

my %common;
$common{$_}++ for keys(%hash1), keys(%hash2);

my @common = grep { $common{$_} > 1 } keys %common;
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