diff --git a/Dockerfile b/Dockerfile
index e851bb72..24d6c8ee 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -26,3 +26,6 @@ ENV HOME /root
 
 # Define working directory.
 WORKDIR /root
+
+# Define default command.
+CMD ["bash"]
diff --git a/README.md b/README.md
index bb3440e7..bb749091 100644
--- a/README.md
+++ b/README.md
@@ -15,4 +15,4 @@ This repository contains **Dockerfile** of [Ubuntu](http://www.ubuntu.com/) for
 
 ### Usage
 
-    docker run -i -t dockerfile/ubuntu bash
+    docker run -it --rm dockerfile/ubuntu