irssi - Irssi is an IRC client.

Irssi is an IRC client program originally written by Timo Sirainen, and
released under the terms of the GNU General Public License in Jan 1999.

It is written from scratch, without using code from other IRC clients,
which makes it more secure, stable and easy to modify.  You can use
language to Perl scripts.  In addition supports IPv6, UTF-8 and
simultaneous connection to several networks.