What's different
Learning to love tmux
Create new session:
screen: screen                      |   tmux: tmux

Create a new session with a name:
screen: screen -S foo       |   tmux: tmux new -n foo

Create a new session with a name but don't attach:
screen: ?????                        |   tmux: tmux new -d -n foo

List sessions:
screen: screen -ls             |   tmux: tmux ls

Attach to a session:
screen: screen -R               |   tmux: tmux a

Attach to a specific session:
screen: screen -r 5238    |   tmux: tmux a -t 2