R startup and shutdown question

Hi R-Community:


Here is what I want to do:


Every time I start R I want R to:


1. remove(list=ls()), and

2. "source" another file automatically.


Then, when I shutdown R, I want R to:


1. remove(list=ls())


How do I do this?


I recall vaguely that S could do this, but I don't remember exactly how 
it worked.


Thanks for your help!


Phil Smith