my %h2 = ( 'AAA' => 'aaa', 'BBB' => 'bbb', 'CCC' => { 'A1' => 'a1', 'B1' => 'b1', 'C1' => { 'A2' => 'a2', 'B2' => 'b2', 'C2' => 'c2END', }, }, 'DDD' => 'ddd', ); sub ddump { my $ref = shift; my $deep = shift||1; for my $k ( sort keys %$ref ) { if ( ref $ref->{$k} ) { print "\t" x $deep."$k =>\n"; ddump( $ref->{$k}, $deep+1 ); } else { print "\t" x ($deep)."$k => $ref->{$k}\n"; } } } ddump( \%h2 );