Operations on a region

[Arnold]

Hi,
I'm a vi user trying to learn emacs.  In vi, I could very easily mark a 
region and do an operation on it.  e.g. :'a,'bs/blah/word/'  or 
:'a,'b!sort.  So far, the closest I've seen is to mark a region and then 
narrow into it, but that's not as easy as on vi and it I can't run a 
command on it and have the output replace that contents of that region.

Lisp is also new to me, but I'm thinking of trying to craft a script 
that will automatically narrow in, prompt me for the search-replace 
stuff, and then automatically widen back out.

Does anyone have a better way, or is this problem perhaps already solved 
already?  

thanks,
arnold