diff --git a/.gitignore b/.gitignore
index 86a55cb0..6fa15f1b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -48,3 +48,4 @@ _site/
 !/preview/html
 
 .DS_Store
+.Rhistory
diff --git a/textbook/09/.Rhistory b/textbook/09/.Rhistory
deleted file mode 100644
index e69de29b..00000000