Notice: Undefined index: HTTP_USER_AGENT in /home/grailgod/ozoneasylum.com/shared/grailapi2.php on line 1468 WTF does RTFM mean? — OZONE Asylum, home of the Mad Scientists
It means 'Read the Fucking Manual' and suggests that the question you asked is pretty basic and would have been more easily answered by addressing some of the basic texts on the subject.
A related one is RTFFAQ but as you are currently reading this then you've obviously followed that advice