Switch between sessions in tmux?
Solution 1:
CTRL-b s
found it! Alex's answer is awesome as well. Note CTRL-b is my prefix, your prefix could be something else.
Solution 2:
You're looking for C-b ( and C-b ). You can find this and many more wonderful tips on the tmux cheatsheet.
Solution 3:
Is PREFIX s but the real command is choose-tree. Then you can use it to bind to other key for example to 'S'
bind S choose-tree
http://man.openbsd.org/OpenBSD-current/man1/tmux.1#choose-tree