What is Linux?

Linux is one of the most widely used operating systems in the world: it powers Android, all of the world’s top 500 supercomputers, and most of the servers that run the internet, according to the Linux Foundation. On the web, it runs 61.7% of all websites whose operating system is known (W3Techs, August 7, 2026).

Developers particularly favor it. The open-source nature of Linux means you can read the code, adapt the OS to your needs, and collaborate with other users on its development.

The kernel and Linux distributions

Strictly speaking, the name Linux belongs to the kernel: the core program that manages a computer’s CPU, memory, and hardware. Linus Torvalds released the first version in 1991 and moved it under the GNU General Public License (GPL) in 1992, the change that made today’s distribution model possible.

The kernel alone isn’t a complete operating system. Kernel.org calls it “just a component in a working Linux system”; the complete systems built around it are called distributions, or distros. Each distro packages the kernel with system tools, a package manager, and a preselected set of software, which is why hundreds of them exist and why they can feel so different from each other.

A few names cover most real-world use. Ubuntu leads among the distros W3Techs can identify, running 15.0% of all Linux-run websites as of August 7, 2026, with Debian next at 6.0% and a reputation for rock-solid stability. AlmaLinux and Rocky Linux are community-run systems compatible with Red Hat Enterprise Linux (RHEL), the usual picks when business software targets that platform. Other distros specialize further, from lightweight desktop systems to security testing. Our guide to the 13 best Linux distros of 2026 compares the major options.

Linux vs. Unix

Unix is the operating system that began at AT&T’s Bell Labs in 1969, and its design set the conventions most server systems still follow, per The Open Group. Linux is called Unix-like because it follows those conventions without sharing the code: kernel.org describes the kernel as “a clone of the operating system Unix, written from scratch,” and it aims at POSIX and Single UNIX Specification compliance, the standards that define how a Unix system behaves.

The differences are practical. Unix began as licensed commercial software, and the UNIX name is now a trademark of The Open Group: only certified systems, such as Apple’s macOS, first certified in 2007, and IBM’s AIX, can carry it. Linux distributions skip the certification and cost nothing to license. If you’re picking a server OS in 2026, the Unix you’ll actually use is Linux.

Linux vs. Windows for web hosting

Linux is the web’s default operating system, not the fallback. Unix-family systems, nearly all of them Linux, run 91.9% of websites whose operating system is known, versus 8.3% for Windows (W3Techs, August 7, 2026). That’s why most hosting companies offer Linux hosting as the default. The decision rule is short:

• Choose Linux hosting for WordPress, PHP, MySQL, Python, and nearly every other common web stack. It’s the industry standard, it pairs with web server software like Apache and NGINX, and there’s no OS license fee.
• Choose Windows hosting only if your site depends on Microsoft-specific technology such as ASP.NET or Microsoft SQL Server.

DreamHost servers run Linux, too: dedicated servers run Ubuntu, and VPS plans offer a choice of Ubuntu, Debian, AlmaLinux, or Rocky Linux. If your site runs WordPress, PHP, or anything else that isn’t Microsoft-specific, Linux hosting is the answer.