In the strictest sense, Linux refers to an open-source operating system kernel – the Linux kernel – which Linus Torvalds began developing in 1991. In common parlance, however, the entire operating system is referred to as Linux: in addition to the kernel, this includes user programs, system libraries, the command-line interpreter (shell), and the tools required for configuring and managing the system. A significant proportion of these originate from the GNU project, which is why it is also commonly referred to as GNU/Linux. Further details can be found in the article entitled ‘The Fundamental Components of Linux’.

Open source

The Linux kernel is available under version 2 of the GNU General Public Licence (GPLv2). This means that anyone is free to use, study, modify and redistribute the source code; however, any modified version must be redistributed under the same terms. Both individuals and major hardware and software companies are involved in its development.

Distributions

Versions that bundle the kernel, software, package manager and installer into a single package are known as distributions. Distributions differ in terms of their package managers, release cycles, support periods and configurations. On servers, the most common are Ubuntu, Debian, AlmaLinux, Rocky Linux and CloudLinux, which is optimised for hosting services. On desktop computers, Fedora, Linux Mint and openSUSE, amongst others, are popular. You can read a comparison of these in the article on the most popular Linux distributions.

Where is it used?

• On servers: a significant proportion of web servers, database servers and cloud services run on Linux because it is stable, free and can be easily managed remotely via the command line.
• On mobile devices: Android is based on the Linux kernel.
• In embedded systems: routers, smart TVs, network-attached storage (NAS) and industrial devices.
• On desktop computers: to a lesser extent, but with an increasing number of users.

If your website runs on shared hosting, it is highly likely that it is also powered by Linux, even if you only see the control panel. With your own Linux VPS, you choose the distribution and, as the root user, you have full access to the system.

Which version of Linux is running on the server?

Once logged in via SSH, you can check this using the following commands:

cat /etc/os-release   # a disztribúció neve és verziója
uname -r              # a futó kernel verziója
hostnamectl           # rendszerinformációk egy helyen (systemd alapú rendszereken)

How do you get started?

Linux servers are usually managed via the command line, using an SSH connection. As a first step, it is worth familiarising yourself with the basic Linux commands: navigating between directories, copying and editing files, and managing permissions.