irssi

use irc from terminal.
worked on ubuntu and max OSX.

change nickname
/nick username

join a channel
/join #channel_name

list users in a channel
/names

make user an op
/msg chanserv op #channel_name username
/mode #channel_name +o username

auto connect
/server add -auto -network Freenode irc.freenode.net 6667
/network add -nick username Freenode
/channel add -auto #channel_name Freenode