Is there a way to compare what is in the ports tree with what is installed?

[Byung-Hee HWANG]

On Mon, 2007-11-05 at 14:53 +1300, Brett Davidson wrote:
> ie. If I had a particular version of the ports tree on a server, how 
> could I check to see if any of the programs in that tree were actually 
> installed?
> 
> Is there a simple command or sequence of commands to do this?

Usually i search someting with Google before study man(1) carefully.
Google is best friend for me. And below link is the last result:
http://www.google.com/search?hl=en&q=pkg_version&btnG=Google+Search

Sincerely,

-- 
"Does this man have real balls?"
"You're asking if he is a Sicilian." "NO."
		-- Vito Corleone and Tom Hagen, "Chapter 2", page 66-67