title: Passing variable from shell to email-ext in Jenkins
body: <p>I have Jenkins job that has execute shell part in which I have some variable
  BUILD that is dynamically populated.</p>
  
  <p>After build execution, I want to pass this variable to email-ext plugin Default Content to able to show it's value.</p>
  
  <p>I've tried couple of ways without a success:</p>
  
  <ol>
  <li>Passing this ${BUILD} value in Default Content is not recognized (Only Jenkins environment variables are visible in this context)</li>
  <li>Defined new Jenkins global environment variable and tried to overwrite its initial value in shell context which apparently is not possible</li>
  </ol>
  
  <p>Any idea on how to do this?</p>