title: Why does the path command doesn't work in Docker file
body: <p>This is my docker file</p>
  
  <pre><code># This is a comment
  FROM chapmanb/bcbio-nextgen-devel
  MAINTAINER Sabarish Subramanian
  RUN mkdir /root/software &amp;&amp; cd /root/software &amp;&amp; wget http://bio.math.berkeley.edu     /eXpress /downloads/express-1.5.1/express-1.5.1-linux_x86_64.tgz
  RUN cd /root &amp;&amp; mkdir src &amp;&amp; cd src &amp;&amp; tar xzf ../software/express-1.5.1-linux_x86_64.tgz &amp;&amp;  PATH=$PATH:/root/src/express-1.5.1-linux_x86_64 &amp;&amp; export PATH &amp;&amp; echo $PATH
  </code></pre>
  
  <p>In the new docker container the path is not set.Kindly suggest me a good way to do this.</p>