Typo

Author: glatard

boutiques/README.md

@@ -7,6 +7,6 @@ BIDS app and an example of invocation.
 ## How to use
 
 * Install Boutiques: `pip install boutiques`
-* Run the example: `bosh ./bids-app-example.json -i ./invocation.json`
+* Run the example: `bosh ./bids-app-example.json -i ./invocation.json -e`
   (assumes `ds001` is a valid dataset in the current working
-  directory.)
+  directory.)