title: Call popen with environment
body: <p>In my Lua program i have to catch output from an external program. This external program needs certain environment variables. So i do this:</p>
  
  <pre><code>e = ""
  e = e .. "A=100;"
  e = e .. "B=Hi;"
  e = e .. "C=Test;"
  file = io.popen(e .. "/bin/aprogr")
  </code></pre>
  
  <p>Obviously the argument for popen() may pass the limit (if any) if the environment is large.</p>
  
  <p>Is there any other way to pass the environment to the external program ?</p>