Maybe something along the following lines? 

use strict;
use warnings;

my %nested_hash = ( a => { aa => {aaa => 1,
                                  aab => 2,
                                  aac => 3},
                           ab => {aba => 4,
                                  abb => 5,
                                  abc => 6} },
                    b => { ba => {baa => 7,
                                  bab => 8,
                                  bac => 9},
                           bb => {bba => 10,
                                  bbb => 11,
                                  bbc => 12} } );


my @nodes;

sub walk {
  my $node = shift;

  foreach (sort keys %{ $node }) {
    push @nodes, $_;
    print join(", ", @nodes), "\n";
    walk( $node->{$_} ) if ref $node->{$_};
    pop @nodes;
  }
}

walk( \%nested_hash );

__END__
a
a, aa
a, aa, aaa
a, aa, aab
a, aa, aac
a, ab
a, ab, aba
a, ab, abb
a, ab, abc
b
b, ba
b, ba, baa
b, ba, bab
b, ba, bac
b, bb
b, bb, bba
b, bb, bbb
b, bb, bbc

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In reply to Re: Iterating over nested hash by Perlbotics
in thread Iterating over nested hash by Dirk80

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