Grep Intelligent IRC Client?
 

What is the best expert IRC client (X or console). I want one that can intelligently identify users not by their nick but by their address. So when someone logs out, changes their nick then logs back in, the application can easily identify who that person is. Maybe on a private local profile based system based on addresses than nicks.

If such IRC client doesn't exist, then how about a client that allows grep-like commands to search for users matching a particular address?