use Cwd qw(abs_path);
use File::Basename qw(dirname);
 
my $dir_parent = abs_path(dirname(__FILE__) . '/../');

##</code><code>##

use File::Spec;

my $dir_parent = do {
	my ($vol, $dir, $file) = File::Spec->splitpath(
		File::Spec->rel2abs(__FILE__)
	);
	
	# Go up 1 directory
	my @dirs = File::Spec->splitdir($dir);
	pop @dirs while (@dirs > 1 && $dirs[-1] eq ''); # Clean up
	pop @dirs if @dirs > 1; # Go up 1 real directory.
	$dir = File::Spec->catdir(@dirs);
	
	File::Spec->catpath($vol, $dir);
};

##</code><code>##

use File::Basename qw(dirname);
use File::Spec;

my $dir_parent = File::Spec->rel2abs(
	File::Spec->catdir(
		dirname(__FILE__),
		'..'
	)
);