Few days ago I needed to rotate few log files manually. Log file got too big because of the testing environment logging all data for easier tracking of any possible issues and it got to approx 1.5GB in size.

So after test environment was switched off I needed a clean log files to start with and see if there are any critical errors. There were not, but just in case

So here is what you need to do if you want to rotate the files manually (assuming you are using Linux) :

sudo logrotate /etc/logrotate.d/[file_to_be_rotated ]
   

sudo -v -f logrotate /etc/logrotate.d/mysql-server   
sudo -v -f logrotate /etc/logrotate.d/apache2  
sudo -v -f logrotate /etc/logrotate.d/cacti
   

there are 2 parameters I have used:
-v - Verbose
-f - Force rotation of logs even if not needed

Thats about it. Hopefully it was usefull tip and saved someone's day.