Update tmux status line

tmux.conf

@@ -28,8 +28,10 @@ setw -g mode-mouse off
 # try to set title of terminal tmux is running on
 # set -g set-titles off
 set -g display-panes-time 5000
-set -g window-status-current-format "#I|#W:#T#F"
-set -g window-status-format "#I|#W:#T#F"
+# <Index>|<Command>:<Title><Window flag>
+# Example: `1|emacs:.dotfiles*`
+set -g window-status-current-format "#I|#{pane_current_command}:#T#F"
+set -g window-status-format "#I|#{pane_current_command}:#T#F"
 # set window name automatically from command currently running
 set -g automatic-rename on