What is BitchX/ircII/irssi?
BitchX, ircII and irssi are all separate programs which are foreground processes. They allow you to connect to IRC directly from the shell. They are very useful in the fact they it turns your shell terminal into an IRC client instantly (very useful in circumstances where IRC clients are not allowed on the machine you ssh from).
They are also useful because very little configuration is required, and you can get on IRC instantly without having to install anything.