![Unix history-simple](https://upload.wikimedia.org/wikipedia/commons/7/77/Unix_history-simple.svg)
A Unix-like (sometimes referred to as UN*X or *nix)
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
is one that behaves in a manner similar to a
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...
system, although not necessarily conforming to or being certified to any version of the
Single UNIX Specification. A Unix-like
application
Application may refer to:
Mathematics and computing
* Application software, computer software designed to help the user to perform specific tasks
** Application layer, an abstraction layer that specifies protocols and interface methods used in a c ...
is one that behaves like the corresponding
Unix command or
shell. Although there are general
philosophies for Unix design, there is no
technical standard
A technical standard is an established norm or requirement for a repeatable technical task which is applied to a common and repeated use of rules, conditions, guidelines or characteristics for products or related processes and production methods, ...
defining the term, and opinions can differ about the degree to which a particular operating system or application is Unix-like.
Some well-known examples of Unix-like operating systems include Linux and BSD. These systems are often used on servers, as well as on personal computers and other devices. Many popular applications, such as the Apache web server and the Bash shell, are also designed to be used on Unix-like systems.
One of the key features of Unix-like systems is their ability to support multiple users and processes simultaneously. This allows users to run multiple programs at the same time, and to share resources such as memory and disk space. This is in contrast to many older operating systems, which were designed to only support a single user or process at a time. Another important feature of Unix-like systems is their modular design. This means that the operating system is made up of many small, interchangeable components that can be added or removed as needed. This makes it easy to customize the operating system to suit the needs of different users or environments.
Definition
The Open Group owns the
UNIX
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...
trademark
A trademark (also written trade mark or trade-mark) is a type of intellectual property consisting of a recognizable sign, design, or expression that identifies products or services from a particular source and distinguishes them from others ...
and administers the Single UNIX Specification, with the "UNIX" name being used as a
certification mark. They do not approve of the construction "Unix-like", and consider it a misuse of their trademark. Their guidelines require "UNIX" to be presented in uppercase or otherwise distinguished from the surrounding text, strongly encourage using it as a branding adjective for a generic word such as "system", and discourage its use in hyphenated phrases.
Other parties frequently treat "Unix" as a
genericized trademark. Some add a
wildcard character to the name to make an abbreviation like "Un*x"
or "*nix", since Unix-like systems often have Unix-like names such as
AIX
Aix or AIX may refer to:
Computing
* AIX, a line of IBM computer operating systems
*An Alternate Index, for a Virtual Storage Access Method Key Sequenced Data Set
*Athens Internet Exchange, a European Internet exchange point
Places Belgium
...
,
A/UX
A/UX is Apple Computer's Unix-based operating system for Macintosh computers, integrated with System 7's graphical interface and application compatibility. Launched in 1988 and discontinued in 1995 with version 3.1.1, it is Apple's first official ...
,
HP-UX
HP-UX (from "Hewlett Packard Unix") is Hewlett Packard Enterprise's proprietary implementation of the Unix operating system, based on Unix System V (initially System III) and first released in 1984. Current versions support HPE Integrity Ser ...
,
IRIX
IRIX ( ) is a discontinued operating system developed by Silicon Graphics (SGI) to run on the company's proprietary MIPS workstations and servers. It is based on UNIX System V with BSD extensions. In IRIX, SGI originated the XFS file system and ...
,
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...
,
Minix,
Ultrix
Ultrix (officially all-caps ULTRIX) is the brand name of Digital Equipment Corporation's (DEC) discontinued native Unix operating systems for the PDP-11, VAX, MicroVAX and DECstations.
History
The initial development of Unix occurred on DEC equip ...
,
Xenix
Xenix is a discontinued version of the Unix operating system for various microcomputer platforms, licensed by Microsoft from AT&T Corporation in the late 1970s. The Santa Cruz Operation (SCO) later acquired exclusive rights to the software, and ...
, and
XNU
XNU is the computer operating system (OS) kernel developed at Apple Inc. since December 1996 for use in the Mac OS X (now macOS) operating system and released as free and open-source software as part of the Darwin OS, which in addition to macOS ...
. These patterns do not literally match many system names, but are still generally recognized to refer to any UNIX system, descendant, or work-alike, even those with completely dissimilar names such as
Darwin/
macOS
macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lapt ...
,
illumos/
Solaris
Solaris may refer to:
Arts and entertainment Literature, television and film
* ''Solaris'' (novel), a 1961 science fiction novel by Stanisław Lem
** ''Solaris'' (1968 film), directed by Boris Nirenburg
** ''Solaris'' (1972 film), directed by ...
or
FreeBSD
FreeBSD is a free and open-source Unix-like operating system descended from the Berkeley Software Distribution (BSD), which was based on Research Unix. The first version of FreeBSD was released in 1993. In 2005, FreeBSD was the most popular ...
.
In 2007, Wayne R. Gray sued to dispute the status of UNIX as a trademark, but lost his case, and lost again on appeal, with the court upholding the trademark and its ownership.
History
![Unix timeline](https://upload.wikimedia.org/wikipedia/commons/c/cd/Unix_timeline.en.svg)
"Unix-like" systems started to appear in the late 1970s and early 1980s. Many