WeeChat is a free and open-source Internet Relay Chat client, which is designed to be light and fast. More info here.

Buffers:

^p		# switch buffers
/close		# same as /buffer close
^s / ^u		# Set unread marker on all windows
^p, A-left	# Switch buffer left
^n, A-right	# Switch buffer right
A-a		# Next buffer with activity
A-0...9		# Switch buffers
A-w A-Left	# Switch windows
A-w A-b		# Balance windows

Window commands:

/window splith	# Split horizontal
/window splitv	# Split vertical
/window zoom	# Zoom

Search:

^r		# Search
Enter ^j ^m	# Stop search