What do I do with a deb file?

Install Software Using Apt Command

deb files, they are designed to primarily handle package names (for example teamviewer, apache2, mariadb etc..) and they retrieve and install . deb archives associated with a package name, from a source specified in the /etc/apt/sources.

What are deb files in Linux?

deb is used to signify a collection of files managed by the Debian packages management system. So, deb is an abbreviation for Debian package, as opposed to source package. You can install a downloaded Debian package using dpkg in a terminal: dpkg -i *.