diff --git a/tmux.conf b/tmux.conf
index eff2b84..0b8df31 100644
--- a/tmux.conf
+++ b/tmux.conf
@@ -26,7 +26,8 @@ if-shell -b '[ "$(echo "$(tmux -V | cut -c 6-) >= 2.1" | bc)" = 1 ]' \
     bind -n WheelDownPane select-pane -t= \\; send-keys -M; \
     "
 
-# Mac OS X fix for pbcopy, pbpaste, and launchctl
+# Mac OS X fix for pbcopy, pbpaste, and launchctl. Requires:
+# brew install reattach-to-user-namespace
 if-shell -b '[ -n "$(command -v reattach-to-user-namespace)" ]' \
     " \
     set-option -g default-command 'reattach-to-user-namespace -l $SHELL'; \