learntmux.dev
Task 3 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

Add and remove key bindings

Goal

A key selected window 10 and was unbound; | and - split; M-n switches windows with no prefix.

Four commands run the whole key system:

bind key command
add a binding you press after C-b
bind -n key command
add one that needs no prefix at all
unbind key
remove a binding
list-keys -T prefix key
show what a key currently does

Bindings live in key tables, and the table decides when a key applies:

prefix
keys pressed after C-b; where bind writes by default
root
keys with no prefix; -n is short for -T root
copy-mode / copy-mode-vi
only inside copy mode

bind replaces whatever the key did before, silently. And a careless -n binding fires on every keystroke, so leave it off unless you mean it.

Do this

Press C-b :, type bind M-0 selectw -t:=10, Enter, then press C-b M-0.

Window 10, far, is current.

Run open ~/.tmux.conf, add these lines, and save with Ctrl-S:

bind | split-window -h
bind - split-window -v
bind -n M-n next-window

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

C-b | now splits left and right; plain M-n changes window with no prefix.

Press C-b :, type unbind M-0, Enter.

list-keys -T prefix M-0 now reports an unknown key.

Exact window targets

In -t :=10, the : says the target is a window and the = demands an exact match on index 10 — without it, 10 would also match a window whose name merely starts that way.

In the configuration file | needs no quoting; only the shell treats it specially.

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. Some key in the prefix table selects window 10— not done yet
  2. Window 10 is now the current window of session learn— not done yet
  3. The | key in the prefix table splits the window left/right— not done yet
  4. The - key in the prefix table splits the window top/bottom— not done yet
  5. M-n in the root table runs next-window— not done yet
  6. M-0 no longer has a binding in the prefix table— not done yet