Levels 78–81: Terminal Multiplexing

Level 78: Starting tmux

An SSH session that drops kills every process running inside it, unless that process is running inside tmux. A tmux session lives on the server itself, independent of any one connection to it.

Command	What it does
`tmux new -s deploy`	Start a new, named session
`tmux ls`	List running sessions
`tmux attach -t deploy`	Reattach to a named session
`tmux kill-session -t deploy`	End a session entirely, from outside it

Level 79: Windows Inside a Session

One session can hold multiple windows, each a full separate terminal screen, closer to browser tabs than anything else.

Command	What it does
`tmux new-window`	Create a new window in the current session
`tmux new-window -n logs`	Create and name it in one step
`tmux rename-window deploy`	Rename the current window
`tmux next-window`	Switch to the next window
`tmux list-windows`	List every window in the session

Level 80: Panes

Command	What it does
`tmux split-window -h`	Split side by side (the divider runs vertically)
`tmux split-window -v`	Split stacked (the divider runs horizontally)
`tmux select-pane -R`	Move focus right (`-L`/`-U`/`-D` for the others)
`tmux resize-pane -R 10`	Resize by 10 cells in a direction
`tmux kill-pane`	Close the current pane

Level 81: Detach & Reattach

This is the entire reason tmux exists for a sysadmin: a long-running job survives an SSH connection dropping, on purpose.

Command	What it does
`tmux detach` (or Ctrl-b d)	Leave the session running, disconnect cleanly
`tmux attach`	Reattach to the most recently used session
`tmux attach -d`	Reattach, force-detaching every other connected client
`tmux ls`	Prove a job survived a dropped connection: if the session’s still listed, whatever was running inside it never stopped

Finish this tier and move on to TUI Toolbelt: a file manager, two approaches to terminal music, a resource monitor, and the fuzzy finder that ends up wired into everything.