Tmux can be used remotely and it can be run as a daemon. That means you can log onto a remote server start up tmux and then disconnect. Once you log on again you can reattach to your last tmux session and continue where you started off.
So if you like you can fully develop on a remote machine, turn off your computer at night and start again where you left the night before by just reattaching. So in a way you are right, tmux and iTerm2 share some common ideas and features but iTerm2 is just for your local convenience while tmux has some extra features. Besides all that goodness you can even have someone join your tmux session and share one shell with a person from around the globe.
![Install Install](/uploads/1/2/5/4/125499871/157059779.png)
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