How do I set a variable in the configuration file setting.php and use it from code? How do I set a variable in the configuration file setting.php and use it from code?
in settings.php:

$conf['yoursite_something'] = 5;


Then, in your code:

// Second argument is the default.
variable_get('yoursite_something', NULL);


Make sure to prefix the variables, either with the module you're using it in or with the site name.