$hash{$name}{$id}= $comment;
push @{$hash{$name}{$id}}, $comment;  #this one has been commented out

##</code><code>##

my %hash;
my ($name, $id, $comment);

while(<DATA>){
              chomp;
              my ($name, $id, $comment)=split;
              $hash{$name}{$id}= $comment;          #adding comment to related $name/$id..


              #push @{$hash{$name}{$id}}, $comment; #create an anonymous array
                                                    #in case more than one $comment or other variables related to same $name/$id
              }

##</code><code>##

Name1 12 firstname1 some more info

##</code><code>##

for my $key1(sort keys %hash){
    print "$key1\t->$hash{$key1}\t";        #$hash{$key} hash reference,to access it dereference it.....
    foreach $key2(sort keys %{$hash{$key1}}){
            print "$key2\t->$hash{$key1}{$key2}\t\n";
            }
    }

##</code><code>##

use strict;
use warnings;
my %hash;
my ($name, $id, $comment);
while(<DATA>){
              chomp;
              my ($name, $id, $comment)=split;
              $hash{$name}{$id}= $comment;


              #push @{$hash{$name}{$id}}, $comment;
              }


print "Key\t\t Val\t\t Key\t Val\n";
print "---------------------------------------------------\n";


for my $key1(sort keys %hash){
    print "$key1\t->$hash{$key1}\t";
    foreach my $key2(sort keys %{$hash{$key1}}){
            print "$key2\t->$hash{$key1}{$key2}\t\n";
            }
    }

use Data::Dumper;
print Dumper(\%hash);
__DATA__
Name1 12 firstname1
Name2 55 firstname2
Name3 20 firstname3

##</code><code>##