Thanks for the reply, it works, and also I read again those references. a related issue, say:

if somebody enter this url in the browser: http://sample.com/not_exist_url

and I'd like to redirect it to

http://sample.com/

with the try_files approach, index.html got displayed, that's right, but the url in browser still remain as http://sample.com/not_exist_url, i'm looking for a 302 i believe, any suggestions? thanks.

Angelo