How to Count the number of active user in a website without using database or saving number in file using PHP

How to Count the number of active user in a website without using databa开发者_Go百科se or saving number in file using PHP.

ex. you and i are login/using a website how can i know that there are 2 active users in the wbsite?

Does anyone know a function/method for this?

If the case for 'active users' is a login and session, and you have coded your site such that only logged in users get a session, you could get a rough estimate of 'active users' by counting the number of files in the php session directory. For example, assuming your session is set to /var/lib/php/session you could run something like this periodically.

ls -l /var/lib/php/session | wc -l