A Linux operating system is typically referred to as a distribution. A Linux distribution, or distro, is the installation bundle (usually an ISO image) of an operating system that has a collection of tools, libraries, and additional software packages installed on top of the Linux kernel.
The software collection bundled with the Linux kernel usually consists of a bootloader, shell, package management system, graphical user interface, and various software utilities and applications.
There are hundreds of Linux distributions currently available. Among the most popular are Debian, Fedora, openSUSE, Arch Linux, and Slackware, with many other Linux distributions either based upon or derived from them. Some of these distros are divided into commercial and community-supported platforms.
One of the key differences between Linux distributions is the package management system they use and the related Linux package format. We'll get into more detail on this topic in later chapters. For now, the focus is on choosing the right Linux distribution based on our needs.