title: SSH "Login monitor" for Linux
body: <p>I'm trying to write a script that informs the user when someone has logged in on the machine via ssh.</p>
  
  <p>My current idea is to parse the output of "w" using grep in intervals. </p>
  
  <p>But that's neither elegant nor performant. Has anyone got a better idea how to implement such a program?</p>
  
  <p>Any help would really be appreciated!</p>