# Debian GNU/Linux

**Debian GNU/Linux** is a free, stable operating system built and maintained by volunteers. It emphasizes stability, reliability, and open-source principles. Debian is the foundation for many Linux distributions (Ubuntu, Linux Mint, Proxmox, etc.) and runs everywhere from embedded systems to supercomputers.

On a minimal Debian installation, you get a clean system with apt (package manager), systemd (init system), and a shell. Everything else is installed as needed. Debian prioritizes stability over having the latest versions—packages are tested before release and security updates are provided for years.

```bash
$ apt update                    # update package lists
$ apt install package-name      # install a package
$ systemctl status service      # check service status
$ sudo -l                       # check sudo permissions
```

Debian comes in three release channels: stable (tested, conservative), testing (newer, less tested), and unstable/sid (cutting edge, experimental). Most deployments use stable. Developers often use testing or unstable for newer tools.

## Concepts

 1. [[debian-filesystem|Filesystem]]
 2. [[debian-shell-and-environment|Shell and environment]]
 3. [[debian-users-and-groups|Users and groups]]
 4. [[debian-permissions|Permissions]]
 5. [[debian-text-editors|Text editors]]
 6. [[debian-package-manager|Package manager]]
 7. [[debian-repositories|Repositories]]
 8. [[debian-services-and-systemd|Services and systemd]]
 9. [[debian-processes|Processes]]
 10. [[debian-logging|Logging]]
 11. [[debian-networking|Networking]]
 12. [[debian-configuration-files|Configuration files]]
 13. [[debian-ssh|SSH]]
 14. [[debian-scheduling|Scheduling tasks]]
 15. [[debian-disk-and-filesystems|Disk and filesystems]]
 16. [[debian-kernel-and-modules|Kernel and modules]]
 17. [[debian-locale-and-timezone|Locale and timezone]]
 18. [[debian-development-tools|Development tools]]
 19. [[debian-release-cycle|Release cycle]]
 20. [[debian-building-packages|Building packages]]