title: Bash cannot echo $(hostname) embedded in variable
body: <p>If I echo a string which contains the <strong>$(hostname)</strong> command, then it works fine. For example, run in terminal:</p>
  
  <pre><code>echo "http://$(hostname)/main.html"
  http://artur/main.html
  </code></pre>
  
  <p>But if I get that string from a file (previously doing cat to a variable) when I try to print with echo, it does not works:</p>
  
  <pre><code>$ cat site
  http://$(hostname)/main.html
  $ mysite=$(cat site)
  $ echo $mysite
  http://$(hostname)/main.html
  </code></pre>
  
  <p>What am I doing wrong? Any idea?</p>