learntmux.dev
Task 11 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
Challenge · no new keys

Challenge: write your own tmux.conf

Goal

A fresh server reads your ~/.tmux.conf, and session main starts at window 1.

Every line you need is one you have already written. The new part is when a line takes effect:

source
changes the running server, but windows that already exist keep the numbers they have
a fresh server
runs the file before anything exists, so every line applies from zero

base-index is the line that exposes the difference: it only affects windows created after it is set. That is why proving this file works takes kill-server and a genuinely new session, not a reload.

Do this

Write ~/.tmux.conf so that a fresh server has all of this:

Requirement Line
Prefix is C-a, and C-a C-a sends it through set -g prefix C-a, unbind C-b, bind C-a send-prefix
Mouse on set -g mouse on
Status line at the top set -g status-position top
Session name on the left of the bar set -g status-left '#{session_name}'
r reloads the file bind r source-file ~/.tmux.conf
| and - split the window bind | split-window -h, bind - split-window -v
Copy mode uses vi keys set -g mode-keys vi
Windows number from 1 set -g base-index 1

Run open ~/.tmux.conf, write the lines from the table, save with Ctrl-S.

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

You drop to the plain shell.

Run tmux new -s main.

The bar is at the top and reads main; the window list starts at 1.

Press C-a |.

The window splits — and C-b now does nothing.

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. The server restarted (a new pid) and the new prefix is C-a— not done yet
  2. mouse is on, status-position is top, mode-keys is vi— not done yet
  3. status-left uses the session_name format— not done yet
  4. r sources the file, | splits horizontally, - splits vertically— not done yet
  5. Session main's first window is index 1— not done yet