In Ubuntu, open the “Software & Updates” application. This is what you will see:
Go to the “Updates” tab. In the section “When there are security updates,” select from the dropdown “Download and Install automatically”.
Make sure you also check the boxes beside “Important security updates,” “Recommend updates” and “unsupported updates.” This will automate the updating of system files as well as all the software you have installed (from repository or via PPA). Click “Close.” That’s it.
Enable auto update in Ubuntu server
If you are running a Ubuntu server and would like to automate the security update, here is the way to do it. Type the following command in the SSH session: A pink window will appear and ask if you want to get the system to automatically download and install stable updates. Select “Yes.”
It will then reconfigure the system to automatically install stable updates. That’s it. Let us know if this works for you.