ok, I got a set of index urls that are in the following format: http://www.domain.com/test-to-be-done.html I have revert the site back to an old version, zen-cart, and i have some urls in the zen-cart that are as follow: http://www.domain.com/test_to_be_done.html In htaccess, how can i ensure, that when someone looks for an url in google, click on it, it redirect to correct url in zen cart. Now the tricky part, some urls are ok in the first format on the zen-cart install. Its only the urls with underscore that needs to be as the first format.