to install on osx. If you already had tmux
brew unlink tmux; brew install tmux
>brew install tmux
Warning: tmux-1.9a already installed
Then again:
>brew unlink tmux
Unlinking /usr/local/Cellar/tmux/1.9a... 4 symlinks removed
Warning: tmux-1.9a already installed, it's just not linked
to install on osx. If you already had tmux
brew unlink tmux; brew install tmux