title: My virtualenv does not work after installing zsh
body: <p>I installed zsh, oh-my-zsh. And made zsh as a default shell. But when I try to activate my virtualenv with     </p>
  
  <pre><code>source bin/activate
  </code></pre>
  
  <p>There is no any effect. I mean no errors and also I am not in my virtual environment. Then I entered my earlier bash shell and tried activating but it did not also help?     </p>
  
  <p><strong>updated</strong><br>
  when I create new virtualenv it works well. Then how can I activate older ones?</p>