Happy new year!
Although installing a DEB may seem like a trivial task, I have recently changed how I install DEB packages in Ubuntu and wanted to share this.
The first option, DPKG. Using DPKG it is as simple as the following to install a package:
dpkg -i deb_package_name.deb
This option works, however if the package has dependencies that you do not currently have installed the installation will fail and you will need to install the dependencies as well as finish installing the initial DEB package using APT as follows:
apt install -f
The second option is to use GDebi. GDebi installs the dependencies for the DEB package automatically.
If this outputs a command not found you just need to install gdebi using the following command:
apt install gdebi