tmux/Option/pane-border-format

• pane-border-format

  • Sets the format text shown in pane-border status lines. It accepts tmux formats such as #{pane_index}, #{pane_title}, and #{pane_active}.
  • The text appears when tmux/Option/pane-border-status is set to a visible position.
  • Example: tmux set-option -g pane-border-format ' #{pane_index}: #{pane_title} '

  • The stock value already renders the pane title

    • The manual states no default for this option, so the value has to be read off a server started with no config on the build in use rather than looked up. On tmux/v/3.7b, measured 2026/08/24:
      • sh

        tmux -L stock -f /dev/null new-session -d
        tmux -L stock show-options -gv pane-border-format
        # #{?pane_active,#[reverse],}#{pane_index}#[default] "#{pane_title}"#{?#{mouse},…}
        tmux -L stock kill-server

    • The "#{pane_title}" in there is why naming panes with select-pane -T needs no format of its own: turning tmux/Option/pane-border-status on is the whole of it. This is the reason My/Dotfiles change track-tmux-pane-border-status is one line — the running server's value was identical to stock, character for character, so tracking it would have been upkeep that changed no behavior.
    • Read what a given pane's border line will say, with the format expanded in that pane's context:
      • sh

        tmux display-message -p -t '<session>:<window>.1' '#{E:pane-border-format}'