I am running Ubuntu Server 16.04. Whenever I login it will tell me if I have updates which is great, I will run those updates and go about my business. The next time I login, it tells me that the server needs a restart.
My question is, besides logging out and logging back in, is there a way to tell if the machine needs a reboot?
In essence, you just need to check if this file has been created after updates, configuration changes or security updates: /var/run/reboot-required.
If you need to check which installed packages need the reboot then open the file /var/run/reboot-required.dpkgs