the readme one-liner fails in practice
diff --git a/README.rst b/README.rst
index 610ce38f290..712eb3b225e 100644
--- a/README.rst
+++ b/README.rst
@@ -21,7 +21,7 @@ All you need to do is:
 
 ::
 
-   user@www:~$ sudo letsencrypt www.example.org
+   user@www:~$ sudo letsencrypt -d www.example.org
 
 
 **Encrypt ALL the things!**

It's missing the required -d before the domain name.
