daryl.mu

For Linux I reckon irssi is probably the coolest IRC client out there and has some nifty features for a terminal app. It can be installed with:

sudo apt-get install irssi

One of the first thing you will probably need to do is set it up to auto login.  This can be done in a couple of simple steps:

These instructions use irc.freenode.net but you can change as required. Also obviously replace your_nickname and your_password with the actual values!

1. Start irssi. In a shell:
irssi

2. Join your irc network. Assuming irc.freenode.net in irssi type:
/connect irc.freenode.net

3. Once you’ve connected if you haven’t done already you need to make sure your nickname is correctly registered. In irssi type
/nick your_nickname
/msg nickserv register your_password

4. Now set up irssi to auto connect and identify
/SERVER ADD -auto -network freenode irc.freenode.net 6667 your_password

5. Quit irrsi
/quit

Now anytime you start irssi using your nickname it will auto connect to irc.freenode.net and auto identify! To start irssi with your nick:
irssi -n your_nickname