Linux Distributions
What a Linux Distribution Includes
A Linux distribution, usually shortened to distro, is a complete operating system built around the Linux kernel. It combines the kernel with GNU and other system software, a package manager for installing and updating programs, and default settings chosen by the maintainers. For the kernel itself, see What Is Linux?
The package manager is the part administrators interact with most. It installs software from a repository, resolves dependencies (other packages a program needs) and applies updates. Packages are signed so that the system can verify they have not been altered.
Distributions also decide which init system starts services at boot. Most current distributions use systemd, though the choice is not universal. Each distribution sets its own release policy, which determines how often packages change and how long a release is supported. For a server, that policy is often the most important difference.
The Main Linux Distribution Families
Many distributions share a common ancestor and package format, so they are grouped into families. Knowing the family tells you a lot about how software is packaged and which documentation applies.
The Debian family includes Debian itself and Ubuntu Server, which is derived from it. These systems use the .deb package format and the APT package manager. The Red Hat family includes Red Hat Enterprise Linux, Fedora and several RHEL-compatible rebuilds. These use the RPM package format and the DNF package manager. Arch Linux forms its own family with a separate package format and tooling, and SUSE is another independent lineage.
Why Distributions Matter for Hosting
Hosting providers choose a distribution as a standard, because a single base system simplifies training, automation and support. An image based on a well-known distribution is usually available on virtual private servers and cloud platforms, and software vendors often publish packages for a few major families first.
Distributions differ in support length, default security settings and the age of their software. A conservative release policy may keep library versions older for stability, while a faster-moving one introduces new features sooner. Neither is wrong. The right choice depends on the software you run and how much change you can absorb.
Frequently asked questions
Is a Linux distro the same as Linux?
Not quite. Linux refers to the kernel, while a distribution is the complete operating system that includes the kernel, tools and packages. People often use the words interchangeably in conversation, but for server decisions the distribution determines the packages, support and update schedule.
How many Linux distributions are there?
Hundreds are actively maintained, and many more are derived, experimental or no longer updated. Most are variations on a few families or are built for a specific purpose, such as desktops, embedded devices or security testing. For servers, the choice is usually narrowed to a handful of families with long support.