Ubuntu – regularly run ‘apt-get update’ and similar commands?

aptcleanuppackage-managementupdatesupgrade

I am completely new to Ubuntu. A friend recommended me to frequently run the following commands:

sudo apt-get upgrade
sudo apt-get update
sudo apt-get autoremove
sudo apt-get autoclean

He said that this will somehow keep my system clean and updated. I do not know what exactly these commands do. Is it really useful to run them regularly?

Best Answer

On all currently supported versions of Ubuntu, we can use apt instead of apt-get. If you want to capture the output in a file, use apt-get, but otherwise use apt as its output is more readable (and who likes typing?).

sudo apt update

Downloads information from the repositories 1 APT is configured to check, and updates the dpkg database of available, installed, and uninstalled packages to reflect changes in the repositories. This means that when you query the database on your system with commands like

apt policy package-name
apt show package-name
apt search package-name

they will print accurate information, and when you run commands like

sudo apt install package-name

they will fetch the latest available version.

When you run sudo apt update you may see that some packages are upgradable, meaning new versions have been added to the repositories. Newer versions often have bug fixes and security updates, so you should install them. This can be done by upgrading all packages that have new versions available with the command

sudo apt upgrade

If the kernel was upgraded (packages like linux-image-4.15.0-20-generic) you should then run a command to remove old kernel versions (except for the second-newest which is kept as a spare, in case the new one is buggy). You can use this command:

sudo apt autoremove

to do that. This command also removed orphaned packages. These generally only exist when you use a command like

sudo apt remove package-name

and package-name has dependencies that were installed along with it automatically, but are not needed by any other package.

For autoclean, I refer you to man apt-get

autoclean (and the auto-clean alias since 1.1)
       Like clean, autoclean clears out the local repository of retrieved
       package files. The difference is that it only removes package files
       that can no longer be downloaded, and are largely useless.

The other three commands are really important and should generally be run regularly to keep the system secure and updated and avoid filling the disk with old kernel files, but you probably won't see much difference after running autoclean. The few files it might delete occasionally are unlikely to amount to much.

1These repositories are configured by default, so you usually don't need to do anything with them. They are listed in the file /etc/apt/sources.list and in files in /etc/apt/sources.list.d. APT is strict about the format of these files (for security reasons) and will throw errors if they have bad syntax. If your system has a graphical environment, it will have an option to configure repositories in settings. You need root privilege to do that job.

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