title: File read not interpreting Environment variables
body: <p>When I try to read a file which contains a environment variable HOSTNAME. 
  It is not interpreting its value while reading the file. </p>
  
  <p>For example, if my hostname is <strong>linux1.com</strong>. 
  When I try to read a sample file(Test.txt) below</p>
  
  <pre><code>/var/log/$HOSTNAME
  </code></pre>
  
  <p>using the code below</p>
  
  <pre><code>while read line
  do
  ls -l $line
  done &lt; Test.txt
  </code></pre>
  
  <p>I am expecting it to interpet the $HOSTNAME variable and print it. But it is not working. It is directly doing <code>ls -l /var/log/$HOSTNAME</code>, instead of </p>
  
  <pre><code>ls -l /var/log/linux1.com 
  </code></pre>
  
  <p>The same command is intrepreting the hostname when I run this command in shell. </p>
  
  <p>Any leads on this is highly appreicated. </p>
  
  <p>Thanks. </p>