Install C.I. above root directory

[eluser]betelgeuse[/eluser]
[quote author="xwero" date="1207768876"]that is not a problem just point the $system_folder and $application_folder to the directory above the root and off you go.[/quote]

Just wondering what a sample would look like. I've tried to point CI above the root directory a couple different ways and neither works...

Code:

Changing
$system_folder = "system";
$application_folder = "application";
to
$system_folder = "../system";
$application_folder = "../application";

and trying the full system location /var/www/codeigniter/system.

I'm not quite sure where to change it within.