title: Apache2 service won't start in Ubuntu 15.10
body: <p>I have installed apache2 but it's won't start, when i do</p>
  
  <pre><code>sudo service apache2 start
  </code></pre>
  
  <p>it's give me this problem</p>
  
  <pre><code>Job for apache2.service failed because the control process exited with    error code. See "systemctl status apache2.service" and "journalctl -xe" for details.
  </code></pre>
  
  <p>so when i enter this command </p>
  
  <pre><code> systemctl status apache2.service
  </code></pre>
  
  <p>it's give me this message</p>
  
  <pre><code>● apache2.service - LSB: Apache2 web server
  Loaded: loaded (/etc/init.d/apache2)
  Active: failed (Result: exit-code) since ن 2016-04-11 15:41:07 WEST; min  43s ago
   Docs: man:systemd-sysv-generator(8)
  Process: 19644 ExecStart=/etc/init.d/apache2 start (code=exited, status=2)
  
  11 15:41:07 oussama-UL50VT systemd[1]: Starting LSB: Apache2 web server...
  11 15:41:07 oussama-UL50VT apache2[19644]: /etc/init.d/apache2: 64: .: Can't open /etc/apache2/envvars
  11 15:41:07 oussama-UL50VT apache2[19644]: /etc/init.d/apache2: 76: .: Can't open /etc/apache2/envvars
  11 15:41:07 oussama-UL50VT systemd[1]: apache2.service: Control process exited, code=exited status=2
  11 15:41:07 oussama-UL50VT systemd[1]: Failed to start LSB: Apache2 web server.
  11 15:41:07 oussama-UL50VT systemd[1]: apache2.service: Unit entered failed state.
  11 15:41:07 oussama-UL50VT systemd[1]: apache2.service: Failed with result 'exit-code'.
  11 15:41:07 oussama-UL50VT apache2[19644]: ERROR: APACHE_PID_FILE needs to be defined in /etc/apache2/envvars
  </code></pre>