Updating all ports

[Jack Barnett]

For /usr/ports I sync to just '.'  (dot).  Is that what I want?  
(I want just 'stable' ports, nothing bleeding edge).

for /usr/src I sync to: RELENG_6

But my question, is there a way to go though and say "let's rebuild any 
port" that is newer (via sync) then one I current have?

For example, if I build and install application FooBar-1.0.0 from the 
/usr/ports and the next week FooBar-1.0.7 is there a way to say "yea, 
let's rebuild this" instead of manually building it?  Or at the very 
least, give me a list of changes on which applications need to be 
manually built.

Thanks!