Irssi is a terminal based IRC client for UNIX systems. It also supports SILC and ICB protocols via plugins.
Ranked in these QuestionsQuestion Ranking
Pro Free and open-source
Pro Perl Scripting
Allows the user to create and use perl scripts to perform actions.
Pro Persistent Connection
Pro Command line outputs can be sent to a channel or message
/exec -o figlet "Slant.co"
Allows the modification of IRSSI's look and feel.
Pro Has a plugin for encrypted communications
Con Gives little direction upfront
Actually, Irssi.org has it's own GREAT documentation.
Con Cryptic configuration files
Con Can't do vertical splits
Untrue, there are perl scripts available to do split screens with
Con No GUI
Actually a plus, lower memory overhead