GNU/Linux operating systems

GNU/Linux is a family of free, open-source operating systems built around the Linux kernel, which manages the processor, memory and hardware, combined with system tools from the GNU project and many other contributors. Because the source code is freely available under licences such as the GNU General Public License, anyone may study, modify and redistribute it. This openness has produced hundreds of separate distributions, each bundling the kernel with a chosen set of applications, a desktop environment and an installer.

Distributions differ mainly in their goals and packaging. Debian is known for stability and its large software archive, and serves as the base for Ubuntu, which aims at ease of use on desktops and servers. Other long-established families include Red Hat and its community successors, and openSUSE, formerly SUSE Linux. Mandrake, later Mandriva, was a once-popular desktop distribution now succeeded by community projects. Each distribution uses a package manager, such as APT or RPM-based tools, to install and update software and to resolve dependencies automatically.

A notable category is the live distribution, which boots and runs entirely from a CD, DVD or USB stick without altering the installed system. Knoppix popularised this approach, and Slax is another compact example; live media are widely used for trying Linux, recovering data and repairing systems. Most distributions can be downloaded as a disc image at no cost. Related components such as Video4Linux provide standard interfaces for hardware like webcams and capture cards.

Frequently asked questions

What is the difference between Linux and a distribution?

Linux is the kernel at the core of the system. A distribution packages that kernel with system tools, applications and an installer to form a complete, usable operating system.

What is a live CD?

It is a bootable disc or USB image that runs a full Linux environment from the removable media itself, without installing anything or changing the existing hard disk.

How is software installed on Linux?

Most distributions use a package manager, such as APT on Debian and Ubuntu, which downloads programs from online repositories and handles their dependencies automatically.