What are .deb packages in Ubuntu

There is a chance that you came across the .deb file extension if you use Ubuntu or another Debian-based operating system. But what are these files and why do I need them?

For Ubuntu and many other Linux distributions you often install applications from a package repository. These package repositories contain compiled applications in a certain package format, the format Ubuntu uses is the 'Deb' package format.

A 'Deb', short for Debian, package contains the files necessary for the application with some meta data. In Linux, files are placed in a folder based on their use: binaries may go in /usr/bin and configuration files may go in the /etc folder for example. Besides the meta data in the Deb package, the Deb package specifies where to place which files on your system.

When you run apt install the process above is basically what happens, a .deb file is downloaded from a package repository and then properly unpacked.

You may install a .deb file yourself as well using the dpkg command:

$ dpkg -i <file_path>.deb

A small security notice about the above, only install packages from trusted sources :).