use Data::Dumper;

 $hash = {
     'user1' => {
             'oldpassword' => 0,
             'filesize' => '14360',
             'logins' => 1
      },
      'user2' => {
             'oldpassword' => 0,
             'filesize' => '1220',
             'logins' => 15
      },
      'user3' => {
             'oldpassword' => 1,
             'filesize' => '1780',
             'logins' => 7
      }
};

sub KeysByLogins {
  my $hash = shift;
  map { $_->[1] }
  sort { $a->[0] <=> $b->[0] }
  map { [ $hash{$_}->{logins}, $_ ] } keys %$hash;
}

our @keys = KeysByLogins($hash);
foreach my $key (@keys) {
  print Data::Dumper->Dump([$hash->{$key}], [$key]) . "\n"; # number 1
  #print Data::Dumper->Dump([$hash{$key}], [$key]) . "\n";    # number 2
}

print  $::{hash}. ' ', $::{keys};
##</code><code>##

$user1 = {
           'filesize' => '14360',
           'oldpassword' => 0,
           'logins' => 1
         };

$user3 = {
           'filesize' => '1780',
           'oldpassword' => 1,
           'logins' => 7
         };

$user2 = {
           'filesize' => '1220',
           'oldpassword' => 0,
           'logins' => 15
         };

*main::hash *main::keys