tmux

Refresh source file in all tmux sessions

<C-Space>/<C-B>:source-file ~/.tmux.conf

Rename session

<C-Space>$

Attach to existing session

tmux ls
tmux attach-session -t <session-name>

Attach to seperately controlled tmux session

This wont mirror the view, so you can look at different things in each attached session.
tmux ls
tmux new -t <existing-sesh>