How to set $f* at the root?

[Ingvix]

I am a bit of a beginner still in Clojure so it might be just that, but I just can't figure out how to use the f*! functions to actually set the variable at the root so it's effective globally. I have only managed to insert them with some function that accepts unlimited blocks like render or union. This can provide the same effect, but I can't help but think that I should be able to insert it in the root at the beginning of the file.