Show tmux pane-status only when there is more than one pane in window

Question

I want tmux to show pane statuses only when there is more than one pane in the current window. I have currently devised this which will not work when closing all panes but one in a window (meaning one pane will be left but its status won't get hidden):

# Show pane status only when there is more than one pane
set-hook -g window-linked 'set-option -w pane-border-status off'
set-hook -g window-layout-changed 'if-shell -F "#{!=:#{window_panes}, 1}" "set-option -w pane-border-status top" ; if-shell -F "#{==:#{window_panes}, 1}" "set-option -w pane-border-status off"'
set-hook -g window-pane-changed 'if-shell -F "#{!=:#{window_panes}, 1}" "set-option -w pane-border-status top" ; if-shell -F "#{==:#{window_panes}, 1}" "set-option -w pane-border-status off"'

Answer 1

White space in tmux formats is significant. The expression "#{==:#{window_panes}}, 1}" is always false because of the space character following the comma.

The following hook works as expected under tmux 2.6 by removing the space from both formats

set-hook -g window-layout-changed 'if-shell -F "#{!=:#{window_panes},1}" "set-option -w pane-border-status top" ; if-shell -F "#{==:#{window_panes},1}" "set-option -w pane-border-status off"'

Alternative hook definition using conditional

set-hook -g window-layout-changed 'set-window -F pane-border-status "#{?#{==:#{window_panes},1},off,top}"'

Conditionals are documented at https://man.openbsd.org/OpenBSD-current/man1/tmux.1#FORMATS

Answer 2

I think you almost have it. I had the same question and came up with a simple one line answer (in other words, no need for the three hooks)

is_many="if [ #{window_panes} -eq 1 ]; then exit 1; fi"
set-hook -g window-layout-changed 'if-shell "$is_many" "set-option -w pane-border-status bottom" "set-option -w pane-border-status off"'