title: Where is the environment variable written?
body: <p>I am using Yocto, when i run command <code>env</code>, i could see couple of variables have been set. But when I open up <code>/etc/environment</code>, those variable is not in there. </p>
  
  <p>When i set variable in <code>/etc/environment</code>, for example, proxies, it is not reflected to my system. </p>
  
  <p>How can I know where's the environment variable file?</p>
  
  <p>Thank you.</p>