diff --git a/docker/my_example.Dockerfile b/docker/my_example.Dockerfile
index 18682e4..1164b99 100644
--- a/docker/my_example.Dockerfile
+++ b/docker/my_example.Dockerfile
@@ -12,8 +12,8 @@ FROM osrf/ros:${ROS_DISTRO}-desktop as base
 SHELL ["/bin/bash", "-c"] # change shell to bash because of better compatibility (standard shell would be sh otherwise).
 
 # First checks
-RUN echo "Underlay WS: ${UNDERLAY_WS}"
-RUN echo "Overlay WS: ${Overlay_WS}"
+RUN echo "Underlay WS: \${UNDERLAY_WS}"
+RUN echo "Overlay WS: \${OVERLAY_WS}"
 
 # Create Colcon workspace with external dependencies
 RUN mkdir -p ${UNDERLAY_WS}/src