Diff two address lists?

[Patton]

I have a need to compare two lists of email addresses.  Each one is a 
text file with address per line.  What I need to output is a list of 
email addresses that are only in list B, I do not want the addresses 
that are in both or are only in A.

I've read man diff, and it looks like I should be able to do it, but I 
cannot figure out how to do it and clearly do not understand some of how 
it should work.

I am not married to using diff, anything that will get the result will 
be great.  Any thoughts??


-- 
Patton