diff --git a/Dockerfile b/Dockerfile
index 448ebd5..2b0ba4e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -45,7 +45,7 @@ RUN mkdir -p /guide
 RUN echo "crime1" > /guide/crime1.txt
 RUN echo "crime2" > /guide/crime2.txt
 
-RUN echo 'if [ -f "/guide/$USER.txt" ]; then cat "/guide/$USER.txt"; fi' >> /etc/bash.bashrc
+RUN echo 'if [ -f "/guide/$(whoami).txt" ]; then cat "/guide/$(whoami).txt"; fi' >> /etc/bash.bashrc