A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not conforming to or being certified to any version of the Single UNIX Specification. A Unix-like application is one that behaves like shell. There is no standard for defining the term, some difference of opinion is possible as to the degree to which a given operating system or application is "Unix-like"; the term can include free and open-source operating systems inspired by Bell Labs' Unix or designed to emulate its features and proprietary work-alikes, versions based on the licensed UNIX source code. The Open Group owns the UNIX trademark 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", consider it a misuse of their trademark. Their guidelines require "UNIX" to be presented in uppercase or otherwise distinguished from the surrounding text encourage using it as a branding adjective for a generic word such as "system", discourage its use in hyphenated phrases.

Other parties 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 have Unix-like names such as AIX, A/UX, HP-UX, IRIX, Minix, Xenix, XNU; these patterns do not match many system names, but are still recognized to refer to any UNIX system, descendant, or work-alike those with dissimilar names such as Darwin/macOS, illumos/Solaris or FreeBSD. In 2007, Wayne R. Gray sued to dispute the status of UNIX as a trademark, but lost his case, lost again on appeal, with the court upholding the trademark and its ownership. "Unix-like" systems started to appear in the early 1980s. Many proprietary versions, such as Idris, UNOS, UniFlex, aimed to provide businesses with the functionality available to academic users of UNIX; when AT&T allowed inexpensive commercial binary sub-licensing of UNIX in 1979, a variety of proprietary systems were developed based on it, including AIX, HP-UX, IRIX, SunOS, Tru64, Xenix.

These displaced the proprietary clones. Growing incompatibility among these systems led to the creation of interoperability standards, including POSIX and the Single UNIX Specification. Various free, low-cost, unrestricted substitutes for UNIX emerged in the 1980s and 1990s, including 4.4BSD, Minix. Some of these have in turn been the basis for commercial "Unix-like" systems, such as BSD/OS and macOS. Several versions of OS X/macOS running on Intel-based Mac computers have been certified under the Single UNIX Specification; the BSD variants are descendants of UNIX developed by the University of California at Berkeley with UNIX source code from Bell Labs. However, the BSD code base has evolved since replacing all of the AT&T code. Since the BSD variants are not certified as compliant with the Single UNIX Specification, they are referred to as "UNIX-like" rather than "UNIX". Dennis Ritchie, one of the original creators of Unix, expressed his opinion that Unix-like systems such as Linux are de facto Unix systems.

Eric S. Raymond and Rob Landley have suggested that there are three kinds of Unix-like systems: Those systems with a historical connection to the AT&T codebase. Most commercial UNIX systems fall into this category. So do the BSD systems, which are descendants of work done at the University of California, Berkeley in the late 1970s and early 1980s; some of these systems can still trace their ancestry to AT&T designs. These systems‍—‌largely commercial in nature‍—‌have been determined by the Open Group to meet the Single UNIX Specification and are allowed to carry the UNIX name. Most such systems are commercial derivatives of the System V code base in one form or another, although Apple macOS 10.5 and is a BSD variant, certified, EulerOS and Inspur K-UX are Linux distributions that have been certified, a few other systems earned the trademark through a POSIX compatibility layer and are not otherwise inherently Unix systems. Many ancient UNIX systems no longer meet this definition. Broadly, any Unix-like system that behaves in a manner consistent with the UNIX specification, including having a "program which manages your login and command line sessions".

Most free/open-source implementations of the UNIX design, whether genetic UNIX or not, fall into the restricted definition of this third category due to the expense of obtaining Open Group certification, which costs thousands of dollars for commercial closed source systems. Around 2001, Linux was given the opportunity to get a certification including free help from the POSIX chair Andrew Josey for the symbolic price of one dollar. There have been some activities to make Linux POSIX-compliant, with Josey having prepared a list of differences between the POSIX standard and the Linux Standard Base specification, but in August 2005, this project was shut down because of missing interest at the LSB work group; some non-Unix-like operating systems provide a Unix-like compatibility layer, with varying degrees of Unix-like functionality. IBM z/OS's UNIX System Services is sufficiently complete as to be certified as trademark UNIX. Cygwin and MSYS both provide a GNU environment on top of the Microsoft Windows user API, sufficient for

William Fruet

William Fruet is a Canadian film and television director and screenwriter. He made his directorial debut with the drama Wedding in White, based on a play he had written; the film won Best Picture at the Canadian Film Awards in 1973. His career included several horror films, including Death Weekend, Cries in the Night, Killer Party, as well as television series, including Goosebumps and Poltergeist: The Legacy. Other writing credits include the influential Canadian film Goin' Down the Road, which he co-wrote with Donald Shebib. Fruet began his career as a writer after attending the Canadian Theatre School, his screenwriting credits include Rip-Off, Wedding in White, Death Weekend and Imaginary Playmate, while his film directing credits include Wedding in White, Death Weekend, Spasms and Destroy, Killer Party, Cries in the Night and Bedroom Eyes. Wedding in White, his 1972 film debut starring Carol Kane and Donald Pleasence, was based on a stage play he had written, won the Canadian Film Award for Best Picture in 1973.

His television credits include episodes of The Ray Bradbury Theatre, My Secret Identity, Alfred Hitchcock Presents, Friday the 13th, War of the Worlds, The Outer Limits, Poltergeist: The Legacy, The Zack Files, Da Vinci's Inquest, Chasing Rainbows, Code Name: Eternity and Zoe Busiek: Wild Card. Prior to his career as a writer and director, Fruet had an acting role in the 1963 film Drylanders. William Fruet on IMDb

Belarusian Federation of Radioamateurs and Radiosportsmen

The Belarusian Federation of Radioamateurs and Radiosportsmen is a national non-profit organization for amateur radio enthusiasts in Belarus. The organization uses BFRR as its acronym, based on the standard Romanization of the Belarusian name of the organization; the name of the organization reflects an early purpose of the organization: to support radiosport activities within Belarus. In addition to High Speed Telegraphy and Amateur Radio Direction Finding, BFRR now supports a wide variety of amateur radio activities. Key membership benefits of BFRR include the sponsorship of amateur radio operating awards and radio contests, a QSL bureau for those members who communicate with amateur radio operators in other countries. BFRR represents the interests of Belarusian amateur radio operators before Belarusian and international telecommunications regulatory authorities. BFRR is the national member society representing Belarus in the International Amateur Radio Union. International Amateur Radio Union