title: check if a line is empty using bash
body: <p>I am trying to do a simple comparison to check if a line is empty using bash:</p>
  
  <pre><code>line=$(cat test.txt | grep mum )
  if [ "$line" -eq "" ]
          then
          echo "mum is not there"
      fi
  </code></pre>
  
  <p>But it is not working, it says:  [: too many arguments</p>
  
  <p>Thanks a lot for your help!</p>