diff --git a/docs/CONFIG.md b/docs/CONFIG.md
index b5976dbbb..7abdfc5ff 100644
--- a/docs/CONFIG.md
+++ b/docs/CONFIG.md
@@ -9,6 +9,11 @@ Configuration - a `documentation.yml` file - will accomplish two goals:
 * Organization: you can put top level documentation in order of importance
 * Narration: you can add narrative sections - plain English writing - in
   between autogenerated API documentation.
+  
+Specify the configuration file with the `--config` command-line option.
+```sh
+$ documentation build --config documentation.yml ...
+```
 
 Here's how `documentation.yml` works: