title: Reference to a bash variable whose name contains dot
body: <p>I have a bash variable: <code>agent1.ip</code> with <code>192.168.100.137</code> as its value. When I refer to it in <code>echo</code> like this:</p>
  
  <pre><code>echo $agent1.ip
  </code></pre>
  
  <p>the result is:</p>
  
  <pre><code>.ip
  </code></pre>
  
  <p>How can I access the value?</p>
  
  <p><strong>UPDATE:</strong> my variables are:</p>
  
  <p><img src="https://i.stack.imgur.com/ubaVH.png" alt="enter image description here"></p>