menus of main store's urls are as follow.
http://mainstore.magento6.com/index.php/electronics.html
But menus of the child stores' urls are as follow.
http://store2.magento6.com/catalog/category/view/s/electronics/id/20/
I want to change the url of main store to
http://mainstore.magento6.com/electronics
I want to change the url of child stores to
http://store2.magento6.com/electronics
How can I do it?