Awesome UNIX®

This list is an exploration of the world of UNIX®, including UNIX history, the relevance of UNIX today, and lists select awesome UNIX and UNIX-like projects. This list also contains resources for UNIX standards, programming, communities, and free software. This project is not affiliated with, sponsored, or endorsed by The Open Group.

Frequently Asked Questions
*NIXes
Linux
iOS
Solaris and Illumos®
GNU Hurd
More Unix®-Like Operating Systems
Plan 9® Derivatives
Unix®-like Real Time Operating Systems
Additional Resources
UNIX® and Unix®-Like Hardware Vendors
Intellectual Property Notices

Frequently Asked Questions

What is UNIX

UNIX is the greatest operating system family ever invented you have probably never heard about whose genius design ideas now enable everything great you love.

Why is UNIX relevant today

The ideas behind UNIX®, a research operating system from AT&T in the 1960s, have evolved to form a set of core computer science principles around which dozens of operating systems are built. These operating systems and applications built on them underpin most of modern computing, from the mobile devices in your pocket to mainframes that perform climate change analysis. They exist on a continuum that includes certified UNIX®, open source projects descended from the original AT&T UNIX®, and Unix-like projects designed to be Unix-compatible.

Disambiguation: AT&T UNIX®, UNIX® Certification, UNIX®-Like, and Linux®

Commercial UNIX

UNIX® was originally a research operating system developed at AT&T's Bell Labs.® It has evolved today into a set of operating systems standards, called POSIX® overseen by the IEEE®, and official certifications that can be obtained by companies for their commercial operating systems, through a process administrated by The Open Group®. Among the operating systems certified as UNIX are massive mainframe operating systems like IBM®'s AIX® as well Apple®'s macOS® desktop operating for their MacBook® and iMac® lineup.

"Unix Philosophy"

"Unix philosophy" is a core set of computer science principles, first implemented in UNIX®, now codified in standards set forth by IEEE® and The Open Group®, and duplicated in dozens of UNIX®-like operating systems that emphasize building simple, short, clear, modular, and extensible software on a common set of programming standards and libraries that allow that software to be easily maintained and repurposed by developers other than its creators, across numerous operating systems and platforms. This enables the rapid spread and development of new and better software. It goes hand in hand with open source philosophy.

"This is the Unix philosophy: Write programs that do one thing and do it well. Write programs to work together. Write programs to handle text streams, because that is a universal interface." - Douglas McIlroy, former head of Bell Labs Computing Sciences Research Center

AT&T UNIX®-Derived Descendants, e.g FreeBSD®

The term UNIX also debatedbly encompasses operating systems that are direct descendants of the original AT&T UNIX codebase but have since re-implemented the AT&T code with code under open source licenses. The most prominent of which the family of BSDs: FreeBSD, OpenBSD, and NetBSD, and their derivatives. These are not UNIX® certified, they are technically Unix-like, but share a unique direct link back to AT&T UNIX®, while newcomers like Redox OS do not.

Unix®-Like Operating Systems, e.g. Linux®

For a variety of historical and legal reasons, there has also been a massive explosion of Unix-like operating systems. MINIX®, for example, was created as a Unix-like teaching operating system by Prof. Andrew S. Tanenbaum. Linux® was created because Linus Torvalds, a college student, wanted to run a Unix-like operating system on his own hardware. Linux® has since gone on to become the most popular Unix-like operating system. Twenty years later, when Android, Inc.® needed a kernel for their new namesake mobile operating system they borrowed one from Linux. Unix-like operating systems implement some degree of the POSIX® standards and Unix philosophy but do not seek official UNIX® certification.

*NIXes

Certified UNIX Operating Systems

macOS® - macOS is the current series of Unix-based graphical operating systems developed and marketed by Apple Inc. designed to run on Apple's personal computers.
AIX® - AIX is a series of proprietary Unix operating systems developed and sold by IBM for several of its computer platforms.
HP-UX® - HP-UX is Hewlett Packard Enterprise's proprietary implementation of the Unix operating system, based on UNIX System V.
UnixWare® - UnixWare is a Unix operating system made by Xinuos from the assets of SCO Group.
OpenServer® - OpenServer is a Unix operating system made by Xinuos from the assets of SCO Group.
z/OS® - IBM z/OS is an operating system for IBM zSystems mainframes.

AT&T UNIX®-Derived Operating Systems

These operating systems, with the exception of Open Server 10, are not UNIX® certified by The Open Group.

OpenBSD - OpenBSD is a free and open-source Unix-like computer operating system descended from Berkeley Software Distribution (BSD), a Research Unix derivative developed at the University of California, Berkeley known for its security and development discipline.
- FuguIta - FuguIta is an OpenBSD live CD featuring portable workplace, low hardware requirements, additional software, and partial support for Japanese.
- MirBSD - Fork of OpenBSD that tracks OpenBSD base with a number of enhancements and modifications.
NetBSD® - NetBSD is a free and open source Unix-like operating system that descends from Berkeley Software Distribution (BSD), a Research Unix derivative developed at the University of California, Berkeley known for its wideranging platform support.
DragonflyBSD - DragonFly BSD is a free and open source Unix-like operating system created as a fork of FreeBSD 4.8.
FreeBSD® - FreeBSD is a free and open-source Unix®-like operating system descended from Research Unix via the Berkeley Software Distribution (BSD) known for its software package availability and speed.
- GhostBSD - GhostBSD is a Unix®-like operating system based on TrueOS with MATE as its default desktop environment.
- MidnightBSD - MidnightBSD is a free Unix®-like, desktop-oriented operating system based on FreeBSD 6.1 that borrows heavily from the NeXTSTEP graphical user interface.
- HardendedBSD - HardenedBSD is a security-enhanced fork of FreeBSD. The HardenedBSD Project implements a number of exploit mitigation and security technologies on top of FreeBSD.
- TrueNAS CORE® - TrueNAS CORE (formerly known as FreeNAS®) is a free and open-source network-attached storage (NAS) software based on FreeBSD and the OpenZFS file system.
- pfSense® - pfSense is an open source firewall/router computer software distribution based on FreeBSD.
- OPNsense® - OPNsense originally forked from pfSense in 2014 over technical differences between developers of pfSense.
- Open Server 10® - Xinuos® OpenServer 10® commercial operating system based on FreeBSD 10 and designed to support business applications. 💰
- XigmaNAS - XigmaNAS (formerly known as NAS4Free) is an embedded Open Source NAS (Network-Attached Storage) distribution based on the latest FreeBSD releases.
- helloSystem - helloSystem is a FreeBSD-based desktop system for creators with a focus on simplicity, elegance, and usability. Its design follows the “Less, but better” philosophy. It is intended as a system for “mere mortals”, welcoming to switchers from the Mac.

UNIX-Certified Linux-Based Operating Systems

As of 2023, there are no more UNIX®-certified Linux-based operating systems. The last two being K-UX® from Inspur and EulerOS® from Huawei.

Many Linux-based operating systems include a UNIX® compatability add-on that pass OpenGroup UNIX® compatability suite tests, but the Linux vendors no longer obtain UNIX® certification.

Linux

The Most Popular Unix-Like Operating System. These operating systems are not UNIX® certified by The Open Group.

Most Unix®-Like Engineered Linux Distributions

Slackware - Slackware is a Linux distribution created by Patrick Volkerding in 1993. Slackware aims for design stability and simplicity and to be the most "Unix-like" Linux distribution.
- Salix - Salix is a Linux distribution based on Slackware that is simple, fast, and easy to use. Salix adds automated dependency resolution, a larger repository of applications, and a suite of native administration and configuration tools for both the GUI and the command line.
Devuan - Devuan Linux is a fork of Debian without systemd from Unix veterans with the goal of becoming the new go-to base distribution for Linux. XFCE is default desktop environment.
- heads - Heads is a live CD to connect securely over Tor, unlike Tails it does not rely on systemd or non-free software. awesome is default desktop environment.
- Gnuinos - Gnuinos is a lightweight Linux libre distro based on Devuan with no non-free software featuring OpenBox desktop.
Gentoo® - Gentoo is a Linux distribution built using the Portage package management system. Unlike a binary software distribution, the source code is compiled locally at the time of installation. Gentoo is known for its speed.
- Funtoo - Funtoo Linux is a Linux-based operating system that is a variant of Gentoo Linux.
- Redcore - Redcore Linux is a distribution based on Gentoo Linux that aims to be a very quick way to install a pure Gentoo Linux system without spending hours or days compiling from source code.
Alpine - Alpine Linux is an independent, non-commercial, general purpose Linux distribution designed for power users who appreciate security, simplicity and resource efficiency.
- Adélie - Adélie Linux was created by Gentoo users who combined the power of Alpine with the ease-of-use of a binary package manager. Adélie is notable for supporting x86, PowerPC, MIPS, and ARM platforms.
Void - Void is a general purpose operating system, based on the monolithic Linux kernel, features XBPS packaging system.
GuixSD - GuixSD is an advanced distribution of the GNU operating system developed by the GNU Project, home of gcc and the GPL, which respects the freedom of computer users.
Linux From Scratch - Linux From Scratch is a way to install a working Linux system by building and installing all components manually, including the bootloader, kernel, and user programs.
Dragora - The Dragora project produces a libre, reliable, Unix-like GNU/Linux distribution made from scratch.

Popular Commercial Linux® Distributions

Ubuntu® - Ubuntu is a Debian-based Linux distribution published by Canonical® who offer commercial support for enterprise-class Ubuntu Server variant.
- Pop!_OS - POP!_OS is a developer and maker-focused minimalist Linux distro from Linux hardware manufacturer System 76®. It runs on any x86-compatible hardware.
- elementaryOS - Distro elementaryOS is a consumer-oriented Linux distribution based on Ubuntu. It is the flagship distribution to showcase the Pantheon desktop environment. 💰
Red Hat Enterprise® - Red Hat Enterprise Linux is a Linux distribution developed by Red Hat® and targeted toward the commercial market. 💰
SUSE Linux Enterprise® - SUSE Linux Enterprise workstation/server is a Linux-based operating system developed by SUSE®. It is designed for servers, mainframes, and workstations. 💰
Oracle® - Oracle Linux® is compiled from Red Hat Enterprise Linux source code, replacing Red Hat branding with Oracle's, optimized to run Oracle software. 💰
Deepin - Deepin is a popular Chinese Linux distribution based on Debian with a focus on being a user-friendly desktop Linux distribution. It includes a number of pre-installed proprietary applications, such as Skype.
Clear Linux - Clear Linux is a distribution developed and maintained by Intel, the makers of Intel computer processors. The distribution is heavily optimized for Intel processors at the kernel and library levels. As a result is it one of the highest performing Linux distros on x86_64 hardware.

Popular Non-Commercial Linux® Distributions

Debian® - Debian is a Unix-like computer operating system that is composed entirely of free software, most of which is under the GNU General Public License and packaged by a group of individuals participating in the Debian Project.