copy mode in tmux

1. Use ctrl-b [ to enter copy mode in tmux
2. Use h j k l keys to move around.
3. Use space key to start selection.
4. Use enter key to copy the selected text.
5. Use ctrl-b ] to paste the copied text.

# man tmux

http://www.openbsd.org/cgi-bin/man.cgi?query=tmux&sektion=1