diff --git a/README b/README
index 9401251..d5ab82e 100644
--- a/README
+++ b/README
@@ -25,7 +25,9 @@
     git clone https://github.com/joewalnes/websocketd
     (cd websocketd && make)
 
-    sudo websocketd/websocketd --port=8000 --staticdir=web --binary ./nbd-proxy
+    sudo websocketd/websocketd --port=8000 --staticdir=web --binary ./nbd-proxy <config>
+
+- where <config> is a name of a configuration in the config.json file.
 
 Note that this type of invocation is very insecure, and intended just for
 experimentation. See the Security section below.