How to resize a tmux pane?
Short answer
tmux resize-pane -L 10 # push the active pane's border 10 columns to the left
tmux resize-pane -R 10 # ... to the right; -U / -D for up / down
tmux resize-pane -x 80 -y 24 # absolute size: 80 columns, 24 rows-L/-R/-U/-D [N] moves the border in that direction by N cells (default 1). -x/-y set an exact
size in columns and rows. Both target the active pane unless you pass -t.
Details
A resize only does something when there is a neighbour on that axis to trade space with. Two panes sitting side by side share a vertical border, so you can change their widths but not their heights: there is nothing above or below to give a row back to. Stack a third pane and the vertical resize starts working.
From the keyboard the binds are repeatable (-r), so you hold the modifier and tap the arrow keys
instead of typing the command each time:
prefix C-Up / C-Down / C-Left / C-Right resize-pane -U/-D/-L/-R (step 1)
prefix M-Up / M-Down / M-Left / M-Right resize-pane -U/-D/-L/-R 5 (step 5, Alt)This nudges one border at a time. To rearrange every pane at once, change the layout instead
(prefix Space cycles the presets, or tmux select-layout tiled).
Verified on tmux 3.2a.