Debian is a free and open-source operating system (OS) based on the Linux kernel. It is one of the oldest and most influential Linux distributions, known for its stability, reliability, and commitment to free software principles.

Debian was first released in 1993 by Ian Murdock and has since grown into a large and diverse community-driven project. It follows a strict commitment to free software, which means it emphasizes using open-source software and avoids including proprietary components by default. However, it also offers repositories of non-free software for users who choose to install it.

One of the key features of Debian is its package management system, known as Advanced Package Tool (APT). APT allows users to install, upgrade, and remove software packages from the Debian repositories. It simplifies the software management and ensures that dependencies are properly handled.

With over 59,000 packages in its repositories Debian is known for its wide range of software packages. It supports multiple architectures, including Intel x86, ARM, PowerPC, and more. Debian has three main branches: Stable, Testing, and Unstable. The Stable branch is recommended due to its focus on stability and reliability, while the Testing and Unstable branches offer more up-to-date software but with a higher risk of potential bugs.

Debian has influenced many other Linux distributions, including Ubuntu and Linux Mint. Its commitment to open-source principles, stability, and community-driven development has made it a popular choice among Linux users, from individual desktop users to large-scale server deployments.