title: How to set bash environment variables using lua
body: <p>I am new to lua script features.
  I tried using,</p>
  
  <ol>
  <li>os.execute("export MY_VAR=10")</li>
  <li>io.popen("export MY_VAR=10")</li>
  </ol>
  
  <p>from lua script.</p>
  
  <p>I try reading MY_VAR variable from shell using echo $MY_VAR after lua script is executed but I do not see MY_VAR getting set to 10.</p>
  
  <p>How do we set the environment variable using lua script?</p>