sub main
{
   my (%hash_rec) = ();
   $hash_rec{'id'} = "001";
   &doSub1(\%hash_rec);

   # return result should consist of id=001 and id2=002
   print "back main, id=$hash_rec{'id'}, id2=$hash_rec{'id2'}\n";
}

sub doSub1
{
   my ($hash_ref) = @_;
   print "inside doSub1, id=$$hash_ref{'id'}\n";
   $$hash_ref{'id2'} = "002";
   
   # How do I call doSub2 and pass only specific hash id2 as reference?
   &doSub2($hash_ref{'id2'});
}


sub doSub2
{
   my ($id2_ref) = @_;
   print "inside doSub2, id2=$$id2_ref\n";
}