learntmux.dev
Task 2 of 11
Level 1 · BasicsOverview
  1. 1Start your first session
  2. 2The prefix key and new windows
  3. 3Find any key with the help list
  4. 4Run commands from the command prompt
  5. 5Detach and come back
  6. 6Read the session list and juggle sessions
  7. 7Split the window into panes
  8. 8Split with flags
  9. 9Move between panes
  10. 10Kill the server
  11. 11Challenge: morning on the build boxchallenge
Level 2 · IntermediateOverview
  1. 1Change the current window
  2. 2Rename the session and a window
  3. 3Kill a pane, a window and a session
  4. 4Zoom a pane
  5. 5Resize panes
  6. 6Apply window layouts
  7. 7Mark and swap panes
  8. 8Move and renumber windows
  9. 9Browse in tree mode
  10. 10Tag and kill from the tree
  11. 11Kick out a stale client
  12. 12Challenge: tidy a messy sessionchallenge
Level 3 · AdvancedOverview
  1. 1Copy text in copy mode
  2. 2Scroll, search the scrollback and paste
  3. 3Choose and delete buffers in buffer mode
  4. 4Name, save and load buffers
  5. 5Find a window by its content or name
  6. 6Use the mouse
  7. 7Break out, join and send keys
  8. 8Challenge: recover the secret from the logschallenge
Level 4 · ConfigureOverview
  1. 1Show, set and unset options
  2. 2Write the configuration file
  3. 3Add and remove key bindings
  4. 4Change the prefix key
  5. 5Customize the status line
  6. 6Formats and embedded styles
  7. 7Embedded shell commands
  8. 8Configure the pane border
  9. 9Use vi keys in copy mode
  10. 10Mouse copying behaviour
  11. 11Challenge: write your own tmux.confchallenge
Cheat sheet

Write the configuration file

Goal

~/.tmux.conf sets mouse on, and a fresh server starts with it on, unsourced.

~/.tmux.conf is a list of tmux commands, one per line, run when the server starts. # starts a comment.

the file
runs once, at server start
source ~/.tmux.conf at C-b :
runs it against the server already running, so you can test without restarting

That distinction is the whole lesson. Starting a new session inside a running server does not re-read the file. And anything you set by hand disappears when the server exits, while anything in the file comes back every single start.

Do this

Run echo '# turn on mouse support' >> ~/.tmux.conf, then echo 'set -g mouse on' >> ~/.tmux.conf.

Two lines now sit in the file. >> appends; > would overwrite it.

Press C-b :, type source ~/.tmux.conf, Enter.

tmux show -g mouse now prints mouse on.

Press C-b :, type kill-server, Enter.

You drop to the plain shell, and the hand-set option goes with the server.

Run tmux new -s learn.

The new server read the file first: tmux show -g mouse prints mouse on with no sourcing.

How the configuration file is parsed

It is not a shell script. ~ and quotes work; $() does not.

Stuck on this one?

This is a live terminal. Typing goes to the machine, including Tab. Press Shift and Tab together to move focus back out to the page.

A real terminal, in this tab

about 15 MB, once

session learn

Done when

not started
  1. ~/.tmux.conf contains the set -g mouse on line— not done yet
  2. The running server has mouse set to on after sourcing the file— not done yet
  3. The old server no longer answers— not done yet
  4. A different server is running and it read the configuration file at start— not done yet