apt update       # Fetches the list of available updates
apt list --upgradable # see list of packages that can be upgraded
apt upgrade      # Installs some updates; does not remove packages
apt full-upgrade # Installs updates; may also remove some packages, if needed
apt autoremove   # Removes any old packages that are no longer needed
apt clean        # clean cache

dpkg -I <package_name>.deb

dpkg -c <package_name>.deb

apt list --installed

apt-mark showmanual

apt-get remove --auto-remove <package_name>

apt-get clean

lsb_release -a

This describes how to install Ubuntu as a VirtualBox guest system to do experiments with docker or other stuff.

• download a server version of Ubuntu
• the current LTS version might be a good idea
• do normal installation

To be able to copy and paste to and from the guest system you need a desktop environment like XFCE. XFCE is small compared to GNOME and the minimal installation does not contain LibreOffice and other stuff you do not need. - install tasksel: sudo apt install tasksel - execute tasksel: sudo tasksel - select Xubuntu minimal installation - press tabulatur and select Ok with return key - reboot

• apt install build-essential dkms
• link the VirtualBox Guest Additions iso image to a cd drive
• cd should be auto mounted to somewhere at /media if XFCE or GNOME is installed
• change to that directory and execute installation: sudo ./VBoxLinuxAdditions.run

also see here: https://askubuntu.com/questions/1035030/virtualbox-guest-additions-installation-problem/1047193#1047193

To install docker do not install the package called docker. Docker is a “ System tray for KDE3/GNOME2 docklet applications”. The package you need is called docker.io - install with: sudo apt install docker.io - start with: sudo systemctl start docker - stop with: sudo systemctl stop docker - enable (always start at boot time) with: sudo systemctl enable docker