use Devel::Size qw(size total_size);

         my $size = size("A string");

         my @foo = (1, 2, 3, 4, 5);
         my $other_size = size(\@foo);

         my $foo = {a => [1, 2, 3],
                 b => {a => [1, 3, 4]}
                };
         my  $total_size = total_size($foo);