diff --git a/README.md b/README.md
index fc135ec..c9c2d60 100644
--- a/README.md
+++ b/README.md
@@ -28,4 +28,4 @@ Basic operation:
 
 Recursive book generation:
 
-`python3 cooklangbook.py /path/to/source/dir /path/to/dest/dir`
+`python3 cooklangbook.py -r /path/to/source/dir /path/to/dest/dir`