add reattach-to-user-namespace for Mac OS

.tmux.conf

@@ -134,4 +134,10 @@ bind m command-prompt -p "man page:" "split-window -h 'exec man %%'"
 bind M command-prompt -p "Man page:" "new-window -n 'man %1' 'exec man %1'"
 
 # Double tapping the prefix jumps to last window
-bind-key C-b last-window
+bind-key C-b last-window
+
+##########################################
+### special settings for MacOS
+##########################################
+# url: https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard
+set-option -g default-command "reattach-to-user-namespace -l bash"