tmux panes and windows: split, resize, zoom, swap and close

Pane and window keys at a glance

Choose your prefix and every key on the page follows. The complete list, including floating panes and copy mode, is on the cheat sheet.

How to split a pane

# side by side / stacked
$ tmux split-window -h
$ tmux split-window -v
# new pane 30 columns wide, or 25% of the space
$ tmux split-window -h -l 30
$ tmux split-window -h -l 25%
# new pane on the left (or above, with -v) instead of right/below
$ tmux split-window -h -b
# full-width pane along the bottom, across all existing panes
$ tmux split-window -v -f
# open in the same directory as the current pane
$ tmux split-window -h -c "#{pane_current_path}"
# run a command in the new pane (the pane closes when it exits)
$ tmux split-window -v -l 10 'htop'
# split without moving focus to the new pane
$ tmux split-window -h -d

-l is the size in columns (with -h) or lines (with -v); add % for a percentage of the pane being split. The old -p 25 flag is a shorthand for -l 25% and works again from tmux 3.5; on tmux 3.4 it fails with size missing, so use -l 25% everywhere.

Easier split keys, in the current directory

By default a new pane starts in the session's start directory (where you ran tmux new, or its -c), not the directory you have since moved to with cd. These two lines in ~/.tmux.conf fix that and use keys that look like the split:

bind | split-window -h -c "#{pane_current_path}"
bind - split-window -v -c "#{pane_current_path}"
bind % split-window -h -c "#{pane_current_path}"
bind '"' split-window -v -c "#{pane_current_path}"

Reload with tmux source ~/.tmux.conf. More on bindings in the config guide.

How to move between panes

$ tmux select-pane -L          # left (-R right, -U up, -D down)
$ tmux select-pane -t 2        # pane number 2 in this window
$ tmux select-pane -t work:1.0 # session work, window 1, pane 0
$ tmux last-pane               # the previously active pane

The arrow keys repeat: after the prefix you can press arrows several times within half a second (repeat-time, 500 ms) without the prefix again. Targets like work:1.0 are explained under target syntax. Vim-style keys are a common addition:

bind h select-pane -L
bind j select-pane -D
bind k select-pane -U
bind l select-pane -R

Note that l is last-window by default, so binding it replaces that. If you use Neovim splits too, vim-tmux-navigator lets Ctrl+h/j/k/l cross both without a prefix.

How to resize panes

# move the border 10 cells left / right / up / down
$ tmux resize-pane -L 10
$ tmux resize-pane -R 10
$ tmux resize-pane -U 5
$ tmux resize-pane -D 5
# set an exact size: 80 columns wide, or 30% of the window
$ tmux resize-pane -x 80
$ tmux resize-pane -x 30%
$ tmux resize-pane -y 15
# a specific pane: put -t before the direction
$ tmux resize-pane -t 1 -R 20

Put -t first and the number last. tmux 3.8 accepts resize-pane -R 5 -t 1, but tmux 3.4 reads the 5 as the last argument and fails with too many arguments. In tmux 3.8, resize-pane also moves the edges of floating panes. For a resize key that does not need the prefix every time, add bind -r H resize-pane -L 5 (and J, K, L); -r makes it repeatable.

How to zoom a pane to full screen

The other panes keep running while one is zoomed. Selecting another pane with the arrow keys unzooms the window. Many commands take -Z to keep the zoom, for example select-pane -Z -t 1 or split-window -Z. With the mouse on and pane-border-status set, the [z] control on the pane border zooms too.

How to close a pane (kill pane, unsplit)

# kill the current pane (no confirmation from the command line)
$ tmux kill-pane
# kill pane 2 of this window
$ tmux kill-pane -t 2
# unsplit: kill every pane except the current one
$ tmux kill-pane -a
# kill all other panes whose title is "logs" (tmux 3.8)
$ tmux kill-pane -a -f '#{==:#{pane_title},logs}'

There is no "unsplit" command. Depending on what you want:

• Remove one split: select the pane you do not want and press Ctrl+b x.
• Go back to one pane: tmux kill-pane -a keeps only the current pane.
• Look at one pane without closing the others: zoom with Ctrl+b z.
• Keep the pane but take it out of this window: break it out with Ctrl+b !.

To close panes without the y/n question, add bind x kill-pane to your config. A pane whose program has exited normally disappears; to keep it on screen (for example to read an error), set remain-on-exit on, or failed to keep only panes that exited with an error, and restart it with respawn-pane.

How to swap and rotate panes

$ tmux swap-pane -U            # with the previous pane (prefix {)
$ tmux swap-pane -D            # with the next pane (prefix })
$ tmux swap-pane -s 0 -t 2     # swap panes 0 and 2
$ tmux swap-pane -d -s 0 -t 2  # same, but keep the focus where it is
$ tmux rotate-window           # every pane moves one place (prefix C-o)
$ tmux rotate-window -D        # the other way (prefix M-o)

For panes in different windows, mark one: select it and press Ctrl+b m (its border is highlighted), go to the other pane, and run tmux swap-pane. With no -s, the marked pane is the source. Ctrl+b M clears the mark.

How to break, join and move panes

# current pane becomes its own window (prefix !); -d stays here, -n names it
$ tmux break-pane -d -n logs
# bring window 2's active pane into this window, side by side
$ tmux join-pane -h -s :2
# bring it in as a 30% strip along the bottom
$ tmux join-pane -v -l 30% -s :2
# send the current pane to window 1 of the session "api"
$ tmux join-pane -t api:1
# move-pane is the same as join-pane for tiled panes
$ tmux move-pane -s :3.1 -t :0

join-pane undoes break-pane: it splits the target pane and puts the source pane in the new space, taking the same -h, -v, -b, -f and -l options as split-window. The marked pane (Ctrl+b m) is the default source, so "mark, go to the other window, join-pane" works without any numbers. In tmux 3.8, break-pane -W floats a tiled pane and join-pane tiles a floating one again (see floating panes).

tmux pane layouts

Drawn from the real pane positions tmux 3.8 reports (list-panes -F '#{pane_left} #{pane_top} #{pane_width} #{pane_height}') for four panes in a 160×40 window, with the default main-pane-width (80) and main-pane-height (24). Pane 0 is the main pane.

Ctrl+b Space goes through them in this order: even-horizontal, even-vertical, main-horizontal, main-horizontal-mirrored, main-vertical, main-vertical-mirrored, tiled. The two mirrored layouts and their Ctrl+b Alt+6 and Ctrl+b Alt+7 keys are new in tmux 3.5, so Ubuntu 24.04's tmux 3.4 does not have them. After choosing a layout you can still resize panes by hand.

Real screenshot · tmux 3.8

$ tmux select-layout main-vertical
$ tmux select-layout -E       # spread out evenly (prefix E)
$ tmux select-layout -o       # undo the last layout change
$ tmux next-layout            # prefix Space; previous-layout goes back
# make the main pane 60% wide in the main-vertical layouts
$ tmux set -w main-pane-width 60%
# save the current arrangement and restore it later
$ tmux display -p '#{window_layout}'
$ tmux select-layout '<the string it printed>'

In tmux 3.8, saved layout strings are a small JSON format that includes floating panes; the older format that tmux 3.4 prints, such as f91d,120x40,0,0{60x40,0,0,0,59x40,61,0,1}, is still accepted. A layout string only applies to a window with the same number of panes or fewer.

Pane numbers and pane titles

Panes are numbered from 0 in each window, in layout order, and renumber when one closes. To start at 1 and give yourself longer to read the numbers:

setw -g pane-base-index 1
set -g display-panes-time 3000

Every pane also has a title. Programs can set it, and you can name panes yourself: Ctrl+b T (new in tmux 3.8) asks for a title, or run tmux select-pane -T logs. To show numbers and titles on the pane borders all the time:

set -g pane-border-status top
# optional: what the border shows (this is close to the 3.8 default)
set -g pane-border-format '#{pane_index} "#{pane_title}"'

Real screenshot · tmux 3.8

The [f][z][x] on each border are 3.8 mouse controls: float or tile the pane, zoom it, and kill it. They appear when the mouse is on. To stop programs from renaming your panes, set allow-set-title off.

Synchronize panes: type in all panes at once

There is no default key for it. This binding toggles it (an on/off option set without a value flips) and shows the new state:

bind S setw synchronize-panes \; display 'sync #{?synchronize-panes,on,off}'

Synchronized input skips panes that are in a mode, such as copy mode. It is handy for running the same command on several servers, each SSH session in its own pane, but check every pane before pressing Enter on anything destructive. For scripted fan-out, send-keys to each pane is safer; see scripting tmux.

Panes with the mouse

The mouse is on by default from tmux 3.8. On older versions (3.4 on Ubuntu 24.04, 3.5a on Debian 13), add set -g mouse on to ~/.tmux.conf.

Windows: create, rename, switch and close

# new window named logs, in a directory, running a command
$ tmux new-window -n logs -c ~/app 'tail -f log/dev.log'
# new window right after the current one, in the background
$ tmux new-window -a -d
# rename the current window
$ tmux rename-window editor
# go to a window by number, name, or the last one
$ tmux select-window -t 2
$ tmux select-window -t logs
$ tmux last-window
# close the current window, window 3, or all windows except this one
$ tmux kill-window
$ tmux kill-window -t 3
$ tmux kill-window -a
# list windows in this session, or in every session
$ tmux list-windows
$ tmux list-windows -a -F '#{session_name}:#{window_index} #{window_name} (#{window_panes} panes)'

tmux names a window after the program running in it (automatic-rename) until you rename it yourself. Ctrl+b & asks kill-window logs? (y/n) and closes every pane in the window. To find a window, use Ctrl+b w for a tree with live previews, Ctrl+b f to search window names and contents, or the new tmux 3.8 switcher:

Real screenshot · tmux 3.8

Ctrl+b Tab opens a floating list of windows that narrows as you type (fuzzy matching); Enter goes there, Esc cancels. Ctrl+b Shift+Tab does the same for sessions. Both run the new switch-mode command.

Move, swap and renumber windows

# move the current window to number 5
$ tmux move-window -t 5
# swap the current window with the one to its left / right
$ tmux swap-window -t -1
$ tmux swap-window -t +1
# renumber all windows 0, 1, 2… (or from base-index)
$ tmux move-window -r
# move window "logs" from session work to session api
$ tmux move-window -s work:logs -t api:

# number windows and panes from 1, so they match the keyboard
set -g base-index 1
setw -g pane-base-index 1
# close gaps automatically when a window is killed
set -g renumber-windows on
# move windows left and right with prefix Shift+Left/Right
bind -r S-Left swap-window -d -t -1
bind -r S-Right swap-window -d -t +1

The -d keeps you on the moved window after the swap. Rebinding Ctrl+b Shift+← replaces its default, which moves the visible part of a window larger than your terminal. With the mouse, right-click a window name in the status line and choose Swap Left or Swap Right.

Floating panes (tmux 3.7 and 3.8)

tmux 3.7 added floating panes: panes that sit above the tiled layout, like a pop-up you can keep working in. Ctrl+b * opens one, Ctrl+b @ (3.8) toggles the current pane between floating and tiled, and Ctrl+b g (3.8) moves it to a corner or side. They are covered in detail, with modal panes and how they differ from display-popup, in floating panes.

Frequently asked questions