Panes are splits within a window. You can split a window vertically (top/bottom) or horizontally (left/right), and nest splits arbitrarily. Each pane runs independently, though they share the same window and layout.
Split and navigate panes with these key bindings (prefix = Ctrl+B):
prefix " split vertically (top/bottom)
prefix % split horizontally (left/right)
prefix o next pane
prefix ; last pane (toggle)
prefix arrow keys navigate panes
prefix x kill current pane
prefix z toggle zoom (fullscreen pane)
prefix q show pane numbers (numbered 0-9)
prefix { swap with previous pane
prefix } swap with next pane
prefix ! break pane into new window
Resize panes while holding the prefix:
prefix Ctrl+arrow resize current pane prefix Alt+arrow resize in 5-cell increments
A useful pattern: split a window, then zoom into a pane to work on it full-screen (Ctrl+B z), then zoom back out to see all panes again. Tmux maintains the pane layout when you zoom.
Kill all panes in a window except the current one:
$ tmux kill-pane -a -t session:window
Break the current pane into a new window:
$ tmux break-pane -t session:window -n new-window-name
Join a pane from another window into the current one:
$ tmux join-pane -t session:window -s source-session:window.pane