title: Module not found in virtualenv
body: <p>I use a virtualenv to pip install packages. To run my script, I need the command:</p>
  
  <pre><code>command = "env/bin/python main.py"
  </code></pre>
  
  <p>If I type the command in the terminal directly, it is working. However, if I run it in </p>
  
  <pre><code>os.system(command)
  </code></pre>
  
  <p>The script is stopped and feedback "xxx is not found". I checked that in the latter case, the used python is not the one in the virtualenv, but the one in the system.   </p>
  
  <p>BTW: The suggested answer does not solve my problem.</p>