diff --git a/Makefile b/Makefile
index 985136d3..1b77f1a1 100644
--- a/Makefile
+++ b/Makefile
@@ -13,4 +13,4 @@ coverage:
 	nosetests skimage --with-coverage --cover-package=skimage
 
 run-all-examples:
-	for f in doc/examples/*.py; do python "$f"; done
+	for f in doc/examples/*.py; do python "$$f"; done