print DumpTree($hash, 'Dein Titel', DISPLAY_ADDRESS => 0);

Dein Titel
`- CpuStats 
   |- cpu 
   |  |- idle = 100.00 
   |  |- iowait = 0.00 
   |  |- nice = 0.00 
   |  |- system = 0.00 
   |  |- total = 0.00 
   |  `- user = 0.00 
   `- cpu0 
      |- idle = 100.00 
      |- iowait = 0.00 
      |- nice = 0.00 
      |- system = 0.00 
      |- total = 0.00 
      `- user = 0.00

use YAML qw(Dump);

print Dump($stat);

---
CpuStats:
  cpu:
    idle: 100.00
    iowait: 0.00
    nice: 0.00
    system: 0.00
    total: 0.00
    user: 0.00
  cpu0:
    idle: 100.00
    iowait: 0.00
    nice: 0.00
    system: 0.00
    total: 0.00
    user: 0.00

use DDS;
Dump($ref);

foreach my $k (sort %hash) {
   # wie genau weiter?
}

foreach my $k (sort keys %hash) {
  for my $subkey ( sort keys %{ $hash{$k} } ){
    print $k,":",$subkey,":",$hash{$k}->{$subkey},"\n";
  }
}

schluessel1:Schluessel1.1:ARRAY(0x8063568)
schluessel1:Schluessel1.2:ARRAY(0x80ed310)
schluessel1:Schluessel1.3:ARRAY(0x80f3818)
...
schluessel3:Schluessel3.1:ARRAY(0x8063468)
schluessel3:Schluessel3.2:ARRAY(0x80ed110)
schluessel3:Schluessel3.3:ARRAY(0x80f1818)
...

output(\%hash);

sub output {
   my $hash = shift;
   foreach my $key (sort keys %$hash) {
      if (ref($hash->{$key})) {
         output($hash->{$key}, @_, $key);
         next;
      }   
      print join(' : ', @_, $key, $hash->{$key}), "\n";
   }   
}

print $k,":",$subkey,":",$hash{$k}->{$subkey},"\n";

print $k,":",$subkey,":",$_,"\n" for @{$hash{$k}->{$subkey}};