Irssi is a very interesting IRC client. It runs completely through the command prompt. It runs on Windows, Linux, and Mac OSX. On windows, you can install it through the executable. It will run through DOS/Putty command lines. On Linux, you can either compile it or install from a binary, through apt-get or something similar. It runs through Bash, obviously.
I have found, that for chatting Irssi can be very powerful. You can connect to any number of networks, and rotate through them with ctrl-x, in the same window. Then you can join any channel on that network. It uses an interesting window system, where you change windows with /window #. There are many other features like auto connect etc.
I find myself rotating through the windows a lot to see what’s going on in each, but that’s expected. It’s really not a problem. I like to have my SSH/FTP or whatever else right next to each other in the command prompt. Tabbing programs is great.
There are many plug ins available for Irssi, that are perl scripts. They are very easy to install and run. One thing many people do not like to start is there is no user list off to the side. This can be remedied by installing a user list plug in, something like this http://www.bellot.net/cyril/contribs:irssi-nicklisthoriz . I have yet to use it, since I haven’t really found a need for a nicklist. When you join a channel, it gives you a list of users, that you can generally use the PgUP button to see.
In conclusion, Irssi is a very useful command line based IRC application. I believe the developers did a great job. I’ve enjoyed using it quite a bit, since it keeps my programs more organized, and it’s easy to use. Check it out!