title: How to edit .env file after build completed reactjs
body: <p>i had build react app web page 
  with custom environment variables<br>
  the problem is when i build the script 
  and change the .env variables no thing change in the website !</p>
  
  <p><code>.env</code> file :</p>
  
  <p><code>REACT_APP_SITENAME=TheSiteName App</code></p>