===== Fix Postgrey PID =====
A default install of postgrey on Debian based systems will probably barf up

  Couldn't unlink "/var/run/postgrey.pid" [Permission denied]

error messages when restarting the daemon. To get rid of them do [[https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=630353#15|this]]:

  mkdir /var/run/postgrey
  chown postgrey:postgrey /var/run/postgrey
  sed -i 's/$DAEMON_NAME.pid/$DAEMON_NAME\/$DAEMON_NAME.pid/' /etc/init.d/postgrey
  /etc/init.d/postgrey stop
  rm /var/run/postgrey.pid
  /etc/init.d/postgrey start