GUI in Ubuntu is as much as useless as unreliable. You can never be sure if you have achieved anything on the OS, unless you do it again on Terminal. Most documentations ask you to run scripts and commands on Terminals before you yell at the screen for UX. If your computer happens to be running any Debian derivatives, you would know well what atmosphere I am referring to.

That being said, if you happen to have lost GUI entirely on Ubuntu, there is a command for updating your OS:

sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade

Update command fetches the package index files. Upgrade actually installs the new packages. And, dist-upgrade handles changes in dependences and can remove some packages if necessary.

Be that as it may, this is definitely far from user-friendly approach. There should be a one line command that deals all of this “intelligently”, and when necessary, more apt user can explicitly provide arguments to control the flows manually. But until then, you will be running with 3 lines of commands every time.