learntmux.dev
Task 7 of 8
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

Break out, join and send keys

Goal

tail alone in window 2, the shell pane joined into window 0, and joined-ok printed there.

Panes are not stuck in the window they were born in:

C-b !
break the active pane out into a window of its own
join-pane -s window at C-b :
pull a pane from another window into this one
send-keys -t target text Enter at C-b :
type into a pane you are not even looking at

A pane keeps its program and its history when it moves. Joining the last pane out of a window closes that window, exactly as killing it would.

Targets are written session:window.pane — learn:0.1 is pane 1 of window 0 in session learn.

Do this

With the tail pane active, press C-b !.

It becomes window 2; window 0 has one pane left.

Press C-b 0, then C-b :, type join-pane -s shell, Enter.

Window 0 has two panes and window 1 is gone.

Press C-b :, type send-keys -t learn:0.1 'echo joined-ok' Enter, Enter.

joined-ok prints in the second pane.

How send-keys reads arguments

send-keys sends each argument as keys: a quoted string is typed out literally, and a key name like Enter is pressed as that key. That is why the command and the Enter are two separate arguments.

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 tail pane now lives alone in window 2— not done yet
  2. Window 1 is gone and window 0 has two panes— not done yet
  3. send-keys ran echo joined-ok in the joined pane— not done yet