Linux
By Linus Torvalds and the open-source community
Linux is a free, open-source Unix-like operating system kernel, originally created by Linus Torvalds in 1991, that today forms the foundation for the majority of servers, cloud infrastructure, and countless embedded and mobile devices.
Definition
Linux is a free, open-source Unix-like operating system kernel, originally created by Linus Torvalds in 1991, that today forms the foundation for the majority of servers, cloud infrastructure, and countless embedded and mobile devices.
Overview
Linus Torvalds started Linux as a personal project in 1991 while a student, releasing the kernel source code publicly and inviting other developers to contribute. Combined with GNU system tools and utilities, it grew into a complete, freely available alternative to proprietary Unix systems, distributed today through distributions such as Ubuntu, Debian, Fedora, and Red Hat Enterprise Linux. As a kernel, Linux manages a machine's hardware resources—CPU scheduling, memory, file systems, and device drivers—and exposes them to user-space programs through a stable set of system calls. Distributions package the kernel together with a shell (commonly Bash), package managers, and userland tools into a usable operating system, while container technologies like Docker and Kubernetes rely directly on Linux kernel features such as namespaces and cgroups to isolate workloads. Linux now runs the overwhelming majority of public cloud infrastructure on providers like AWS and Azure, nearly all of the world's supercomputers, and—via a modified kernel—Android, the most widely used mobile operating system. Its openness and portability have also made it the default choice for embedded systems, networking equipment, and the servers behind most of the modern internet.
Key Features
- Open-source kernel licensed under the GPL, free to use, study, and modify
- Monolithic but modular architecture supporting loadable kernel modules and drivers
- Namespaces and cgroups that underpin modern containerization
- Broad hardware support across servers, desktops, embedded devices, and mobile
- Strong multi-user permissions and process isolation model
- Massive distribution ecosystem (Ubuntu, Debian, Fedora, RHEL, Arch, Alpine, and more)
- Powerful command-line tooling and shell scripting support
- Backbone of most public cloud infrastructure and container runtimes
- Powers Android's kernel layer on billions of mobile devices