The History of Linux: How a 1991 Student Project Became the Backbone of the Cloud

Key takeaways

• Linux is a kernel, started by Linus Torvalds in 1991. Most people use it as GNU/Linux or through a distribution.
• It grew from the Unix tradition of the 1970s and from the GNU project, which supplied the compiler and tools.
• The licence mattered. Torvalds moved the kernel to the GPL in early 1992, which let anyone share improvements and companies build on it.
• Distributions (Debian 1993, Red Hat 1995, Ubuntu 2004) and later Android and the public cloud are what spread Linux.
• CentOS Linux is now end-of-life. Today's RHEL-compatible choices include Rocky Linux and AlmaLinux.

What is Linux?

Linux is a kernel: the core of an operating system that talks to hardware, schedules programs and manages memory. By itself it does not give you a shell, a compiler or a desktop. Those come from other projects, mostly GNU, and are bundled by distributions such as Debian, Red Hat Enterprise Linux and Ubuntu. When people say "Linux" they usually mean one of those complete systems.

How did Unix lead to Linux?

Unix started in 1969 at AT&T's Bell Labs, written by Ken Thompson, Dennis Ritchie and colleagues. In 1973 it was rewritten in the C language, which made it unusually portable. Universities received the source, and the University of California, Berkeley produced the BSD variants. Unix gave the world ideas that Linux still follows: multi-user design, a hierarchical file system, small tools connected by pipes, and "everything is a file".

The trouble was cost and licensing. By the 1980s, Unix was commercial and tied to expensive workstations. Students at home on a PC had few options. Andrew Tanenbaum's MINIX, released in 1987, was a teaching system with restrictions on how it could be modified.

What was the GNU project?

In 1983 Richard Stallman announced the GNU project to build a complete, free Unix-like system. In 1985 he founded the Free Software Foundation. Through the 1980s the GNU project produced the pieces people still use daily: the GCC compiler, the Bash shell, glibc and core utilities. What it lacked was a finished kernel. Read the project's own account at gnu.org.

How did Linus Torvalds start Linux?

In 1991, Linus Torvalds, a student at the University of Helsinki, wrote a kernel for his new 386 PC because he wanted something better than MINIX on it. On 25 August 1991 he posted to the comp.os.minix newsgroup:

"Hello everybody out there using minix - I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones."

Version 0.01 was released in September 1991. It was small and could do little. What changed things was the response: people downloaded it, fixed problems and sent patches.

When did Linux become GPL software?

This is a detail many articles get wrong. The earliest releases used a licence that did not allow commercial use. Torvalds moved the kernel to the GNU General Public License with version 0.12 in early 1992. The GPL lets anyone use, change and share the code, provided they pass the same freedoms on. That condition is why companies could build businesses on Linux without any one of them owning it. Linux 1.0 followed in March 1994.

Why is it called GNU/Linux?

The kernel filled the one gap in the GNU system. Putting them together gave the first fully free operating system. The FSF argues the combination should be called GNU/Linux. Most people simply say Linux. Both usages are common, so it helps to know what is meant when you read either.

What is the Linux timeline?

How did distributions change things?

A kernel alone is hard to use. Distributions solved that by packaging the kernel, tools, an installer and a way to update software.

• Slackware (1993) was one of the earliest and is still maintained.
• Debian (1993) was started by Ian Murdock and run by a community. It is the base of many others, including Ubuntu.
• Red Hat (first release in 1995) was founded by Bob Young and Marc Ewing. It grew into Red Hat Enterprise Linux (RHEL), the commercial distribution behind the RHCSA and RHCE certifications.
• Ubuntu (2004) aimed at an easy desktop experience and later became very common on cloud servers.

Each major family (Debian, Red Hat, SUSE, Arch and others) has its own package manager and conventions. Learning one family well transfers to the others.

How did Linux reach servers, phones and the cloud?

Linux spread because it was free, modifiable and good on cheap hardware. Web hosting companies adopted it first. In 2000 IBM announced large-scale support for Linux, which gave it credibility with corporate buyers. Over the next two decades:

• Servers and the cloud. The large public clouds rely heavily on Linux, and containers and Kubernetes are built on Linux kernel features such as namespaces and cgroups.
• Phones. Android uses the Linux kernel. It is Linux at the kernel level, though not a typical desktop distribution.
• Supercomputers. Since 2017 every system on the TOP500 list has run Linux.
• Embedded devices. Routers, TVs and many car systems run embedded Linux.
• Desktop. Desktop use grew more slowly. Desktop environments such as GNOME and KDE and distributions such as Ubuntu made it practical, but Windows and macOS remain dominant on laptops.

What happened with CentOS, RHEL, Rocky and AlmaLinux?

CentOS was for years the free rebuild of RHEL. In 2020 Red Hat announced that CentOS would shift to CentOS Stream, a stream that sits just ahead of RHEL. CentOS Linux 8 ended in December 2021 and CentOS Linux 7 reached end-of-life in June 2024. Rocky Linux and AlmaLinux emerged as community rebuilds that stay compatible with RHEL. For learning, Red Hat also offers a developer subscription for individuals. Check the RHEL life cycle page for current support dates.

Why did Linux succeed?

• The licence. The GPL made it safe for competing companies to contribute to the same code.
• Timing. Cheap PCs, the early web and a missing free Unix created demand. The legal uncertainty around BSD in the early 1990s also helped.
• Open development. Thousands of developers and companies work on the kernel. The Git workflow Torvalds built in 2005 supports that scale.
• Flexibility. The same kernel runs on a watch and on a supercomputer.

One caution: Linux is not automatically secure. Its permission model, open review and fast patching help, but a badly configured server is still vulnerable. Security depends on administration.

Why does this history matter to your career?

Knowing the lineage makes commands and conventions easier to remember. File permissions, pipes, processes and the idea that devices appear as files all come from Unix. The GPL explains how vendors like Red Hat sell support and subscriptions rather than the code itself. The CentOS story explains why employers now ask about RHEL, Rocky and AlmaLinux. If you plan to work in system administration, DevOps or security, this background supports the hands-on skills tested in certifications such as RHCSA.

Next steps

Install a distribution in a virtual machine and run uname -r to see your kernel version, then cat /etc/os-release to see which distribution you are on. When you want a guided path, our Linux course takes you from the command line to administration. To keep reading, see what Linux and the Linux kernel are and the evolution and future of Linux.

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