title: Dockerfile wget fails
body: <p>I have the following code</p>
  
  <pre><code>RUN apt-get update
  RUN apt-get install -y wget     #install wget lib
  RUN mkdir -p example &amp;&amp; cd example     #create folder and cd to folder
  RUN WGET -r https://host/file.tar &amp;&amp; tar -xvf *.tar   # download tar file to example folder and untar it in same folder
  RUN rm -r example/*.tar # remove the tar file
  RUN MV example/foo example/bar # rename untar directory from foo to bar
  </code></pre>
  
  <p>But i get the following errors:</p>
  
  <pre><code>/bin/sh: 1: WGET: not found
  tar: example/*.tar: Cannot open: No such file or directory
  tar: Error is not recoverable: exiting now
  
  </code></pre>
  
  <p>I am a newbie in docker.</p>