title: extracting a variable's value from text file using bash
body: <p>I am using Linux and bash.
  I have a simple text file like below:</p>
  
  <pre><code>VAR1=100
  VAR2=5
  VAR3=0
  VAR4=99
  </code></pre>
  
  <p>I want to extract by means of bash the value of VAR2, that is 5.</p>
  
  <p>How could I do that?</p>