learntmux.dev
Task 8 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

Split with flags

Goal

Window 0 has five panes: a full-width tail pane at the bottom and a full-height pane on the left.

At the prompt, split-window takes flags the keys cannot:

-f
the new pane spans the full width or height of the window, not just the pane you split
-h / -v
side by side, or stacked. Typed out you say which; with neither, tmux assumes -v
-b
put the new pane before the one you split: to the left, or above
-d
leave the active pane where it is

Flags combine: -fhb is all three at once.

Order matters with -f: a full-width pane made first keeps the rows it took, so a full-height pane made after it spans only what is left.

Do this

Press C-b :, type splitw -fv tail -f ~/build.log, Enter.

A pane running tail spans the whole bottom and is active.

Press C-b :, type splitw -fhb, Enter.

A pane spans the full height at the far left and is active.

Press C-b :, type splitw -d, Enter.

A fifth pane appears below it, and the green border stays put.

How this maps to the split keys

C-b % and C-b " are split-window -h and -v with the defaults already filled in — which is why the prompt feels stricter than the keys.

A command after the flags runs in the new pane instead of a shell, the same way new-window takes one.

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. A pane at the bottom of window 0 spans the full width and runs tail— not done yet
  2. A pane at the left of window 0 spans the full height— not done yet
  3. Window 0 of session learn has five panes— not done yet