log out all users from php sessions based website - and superuser shell for shell wildcard expansions

There was a request to log out all users from the website based on this code. At first I thought just restarting the server after applying some updates would do it. But no. 

https://stackoverflow.com/questions/25740705/how-to-log-out-all-active-logged-in-users-in-php-from-admin-side

Since our site was based on php sessions and nothing was being saved to the database for user sessions, here is what worked:

First found the path using a small php page which had the line 

php echo session_save_path()

(or phpinfo would have worked?)

then just 

sudo sh -c 'rm -v /var/lib/php/sessions/sess*'

About why just 

sudo rm sess* 

won't work, that's because the wildcard expansion is done by the shell and not by rm.