Parental Time Limits on Linux Mint

How to add time limits (parental guidance) to Linux Mint (&/or Ubuntu):

sudo add-apt-repository ppa:mjasnik/ppa
sudo apt-get update
sudo apt-get install timekpr

So far this program, seems to be the best for setting both time limits on total minutes of PC use, and hours of operation.

 

(Special thanks to this site for pointing me in the right direction.)