Bourne shellThe Bourne shell (sh) is a shellcommand-line interpreter for computer operating systems. It first appeared on Version 7 Unix, as its default shell. Unix-like systems continue to have /bin/sh—which will be the Bourne shell, or a symbolic link or hard link to a compatible shell—even when other shells are used by most users. The Bourne shell was once standard on all branded Unix systems, although historically BSD-based systems had many scripts written in csh.
C (programming language)General-purpose programming languageC is a general-purpose programming language created in 1972 by Dennis Ritchie. By design, C gives programmers relatively direct access to the features of typical CPU architectures, customized for the target instruction set. It has been and continues to be used to implement operating systems (especially kernels), device drivers, and protocol stacks, though its use in application software is decreasing.
Unix-likeA Unix-likeoperating system (sometimes referred to as a UN*X,*nix or *NIX) is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-like application is one that behaves like the corresponding Unix command or shell.
Plan 9 from Bell LabsPlan 9 from Bell Labs is an operating system designed by the Computing Science Research Center (CSRC) at Bell Labs in the mid-1980s, built on the UNIX concepts first developed there in the late 1960s. Since 2000, Plan 9 has been free and open-source. The final official release was in early 2021.
Operating systemAn operating system (OS) is system software that manages computer hardware and software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, peripherals, and other resources.
Tom DuffThomas Douglas Selkirk Duff (born December 8, 1952) is a Canadian computer programmer. Life and careerEarly lifeDuff was born in Toronto, Ontario, Canada, and was named for his putative ancestor, the fifth Earl of Selkirk. He grew up in Toronto and Leaside. In 1974 he graduated from the University of Waterloo with a B.Math and, two years later, was awarded an M.Sc. from the University of Toronto.
Open sourceOpen source is the practice of publishing digital resources publicly alongside their source code or source files, enabling use, study, modification, and redistribution. It is historically and commonly associated with open-source software, software released with its source code.
Plan 9 from User SpacePlan 9 from User Space (also plan9port or p9p) is a port of many Plan 9 from Bell Labs libraries and applications to Unix-likeoperating systems. Currently it has been tested on a variety of operating systems, including Linux, macOS, FreeBSD, NetBSD, OpenBSD, Solaris and SunOS. The project's name is a reference to the 1950s Ed Wood film Plan 9 from Outer Space.Duff's deviceIn the C programming language, Duff's device is a way of manually implementing loop unrolling by interleaving two syntactic constructs of C: the do-while loop and a switch statement. Its discovery is credited to Tom Duff in November 1983, when Duff was working for Lucasfilm and used it to speed up a real-time animation program.
AlgolAlgol, designated Beta Persei (β Persei, abbreviated Beta Per, β Per), known colloquially as the Demon Star, is a bright multiple star in the constellation of Perseus and one of the first non-novavariable stars to be discovered. Algol is a three-star system, consisting of Beta Persei Aa1, Aa2, and Ab – in which the hot luminous primary β Persei Aa1 and the larger, but cooler and fainter, β Persei Aa2 regularly pass in front of each other, causing eclipses.
Shell scriptA shell script is a computer program designed to be run by a Unix shell, a command-line interpreter. The various dialects of shell scripts are considered to be command languages. Typical operations performed by shell scripts include file manipulation, program execution, and printing text. A script which sets up the environment, runs the program, and does any necessary cleanup or logging, is called a wrapper.
Command-line interfaceA command-line interface (CLI), also known as a command-line shell, is a means of interacting with software via commands – each formatted as a line of text. The concept of interacting with a computer via text evolved over two decades, transitioning from physical hardware to sophisticated software. Before the CLI, computers were programmed using physical switches or punched cards. The shift toward a "command" style interaction began with the use of Teleprinters (Teletypes).Research UnixResearch Unix refers to the early versions of the Unix operating system for DEC PDP-7, PDP-11, VAX, and Interdata 7/32 and 8/32 computers, developed in the Bell Labs Computing Sciences Research Center (CSRC). The term Research Unix first appeared in the Bell System Technical Journal (Vol. 57, No. 6, Part 2 July/August 1978) to distinguish it from other versions internal to Bell Labs (such as PWB/UNIX and MERT) whose code-base had diverged from the primary CSRC version.*As an Amazon Associate I earn from qualifying purchases.