WeeChat
@weechat

WeeChat is a fast, light and extensible chat client. It runs on many platforms like Linux, Unix, BSD, GNU Hurd, Mac OS X and Windows (Bash/Ubuntu and Cygwin).

WeeChat is:

• modular: a lightweight core with optional plugins
• multi-protocols architecture (mainly IRC)
• extensible with C, Python, Perl, Ruby, Lua, Tcl, Scheme, Javascript and PHP
• fully documented and translated into several languages
• a free program released under the GPLv3 license
• an active project with a large community for scripts.