How do you get PHP, Symlinks and __FILE__ to work together nicely?

Question

On localhost. I have the following directory structure:

/share/www/trunk/wp-content/plugins/otherfolders

/share/www/portfolio/wp-content/s

Answer 1

In some case its possible to change working dir and use getenv('PWD'):

$root = dirname(dirname(dirname(getenv('PWD'))));
if (file_exists($root.'/wp-load.php')) {
    // WP 2.6
    require_once($root.'/wp-load.php');
}

And change working directory before run this code:

cd /var/www/wp-content/themes/twenty_twelve/ && php script.php