Linux Distributions
Linux was initially designed by Linus Torvalds for improving Unix OS, and later various open-source projects were initiated on the basis of Linux. Unlike Windows OS or Mac OS, Linux OS is not managed by a single organization. There are many organizations and programmers managing their versions of Linux OS called Linux distributions.
Each distribution includes the Linux kernel (the foundation of the operating system), GNU shell utilities (the terminal interface and commands), and a package management system. Distributions have many common features; however, there are several differences across them.
There is a history of Linux distribution developments. As each distribution was created as a derivative of another distribution, understanding the history is useful. If the mother distribution of two derivatives is the same, the commands in those derivatives tend to be the same.
There are two major groups in Linux distributions based on a package manager (see the next section to learn more about package managers).
Debian-based
- Debian: one of the oldest operating systems based on the Linux kernel, first released in 1993. The current developer is the Debian project.
- Ubuntu: a mostly free Debian-based Linux distribution developed in 2004. The current main developer is Canonical Ltd.
RPM-based
RPM was originally called Red Hat Package Manager
- Red Hat Enterprise Linux (RHEL): a commercial Linux distribution developed by American software company Red Hat, first released in 2000.
- CentOS: a free Linux distribution based on RHEL, first released in 2004. It was supported by Red Hat but is currently being developed by the CentOS project.
- Fedora: RPM-based Linux distribution developed by the Fedora project, released in 2003.
- OpenSUSE: RPM-based Linux distribution developed by the openSUSE project, released in 2005.