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Chsh
chsh (an abbreviation of "change shell") is a command on Unix-like operating systems that is used to change a login shell. Users can either supply the pathname of the shell that they wish to change to on the command line, or supply no arguments, in which case allows the user to change the shell interactively. Usage is a setuid program that modifies the file, and only allows ordinary users to modify their own login shells. The superuser can modify the shells of other users, by supplying the name of the user whose shell is to be modified as a command-line argument. For security reasons, the shells that both ordinary users and the superuser can specify are limited by the contents of the file, with the pathname of the shell being required to be exactly as it appears in that file. (This security feature is alterable by re-compiling the source code for the command with a different configuration option, and thus is not necessarily enabled on all systems.) The superuser can, howev ...
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Unix
Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user 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 others. Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley ( BSD), Microsoft (Xenix), Sun Microsystems ( SunOS/ Solaris), HP/ HPE ( HP-UX), and IBM ( AIX). The early versions of Unix—which are retrospectively referred to as " Research Unix"—ran on computers such as the PDP-11 and VAX; Unix was commonly used on minicomputers and mainframes from the 1970s onwards. It distinguished itself from its predecessors as the first portable operating system: almost the entire operating system is written in the C programming language (in 1973), which allows U ...
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POSIX
The Portable Operating System Interface (POSIX; ) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines application programming interfaces (APIs), along with command line shells and utility interfaces, for software compatibility (portability) with variants of Unix and other operating systems. POSIX is also a trademark of the IEEE. POSIX is intended to be used by both application and system developers. As of POSIX 2024, the standard is aligned with the C17 language standard. Name Originally, the name "POSIX" referred to IEEE Std 1003.1-1988, released in 1988. The family of POSIX standards is formally designated as IEEE 1003 and the ISO/IEC standard number is ISO/ IEC 9945. The standards emerged from a project that began in 1984 building on work from related activity in the ''/usr/group'' association. Richard Stallman suggested the name ''POSIX'' to the IEEE instead of the former ''IEEE-IX''. Th ...
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Comparison Of Command Shells
This article catalogs comparable aspects of notable operating system shell (computing), shells. General characteristics {, class="wikitable sortable sticky-header sort-under" style="width: auto; text-align: center; font-size: smaller;" , - !Shell ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! , - !Thompson shell , Unix, UNIX , sh , 1971 , , Unix, UNIX , Unix, UNIX , , , Text-based Command-line interface, CLI , , , , , , , , , , , - !Bourne shell 1977 version , Version 7 Unix, 7th Ed. UNIX , sh , 1977 , , Version 7 Unix, 7th Ed. UNIX , Version 7 Unix, 7th Ed. UNIX, , , , Text-based Command-line interface, CLI , , , , , , , , , , , - !Bourne shell current version , Various Unix, UNIX , sh , 1977 , , SunOS-5.x, FreeBSD , SunOS-5.x , , , Text-based Command-line interface, CLI , , Since mid 1990s. , , , , , , , if compiled with -DACCT. , , - !POSIX shell , POSIX , sh , 1992 , , , POSIX , , , Text-based CLI , , , , , , , {{small, Unspecifi ...
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IRIX
IRIX (, ) is a discontinued operating system developed by Silicon Graphics (SGI) to run on the company's proprietary MIPS architecture, MIPS workstations and servers. It is based on UNIX System V with Berkeley Software Distribution, BSD extensions. In IRIX, SGI originated the XFS file system and the industry-standard OpenGL graphics API. History SGI originated the IRIX name in the 1988 release 3.0 of the operating system for the SGI IRIS 4D series of workstations and servers. Previous releases are identified only by the release number prefixed by "4D1-", such as "4D1-2.2". The "4D1-" prefix continued to be used in official documentation to prefix IRIX release numbers. Prior to the IRIS 4D, SGI bundled the GL2 operating system, based on UniSoft UniPlus System V Unix, and using the proprietary MEX (windowing system), MEX (Multiple EXposure) windowing system. IRIX 3.x is based on UNIX System V Release 3 with 4.3BSD enhancements, and incorporates the 4Sight windowing system, based o ...
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Silicon Graphics
Silicon Graphics, Inc. (stylized as SiliconGraphics before 1999, later rebranded SGI, historically known as Silicon Graphics Computer Systems or SGCS) was an American high-performance computing manufacturer, producing computer hardware and software. Founded in Mountain View, California, in November 1981 by James H. Clark, the computer scientist and entrepreneur perhaps best known for founding Netscape (with Marc Andreessen). Its initial market was 3D graphics computer workstations, but its products, strategies and market positions developed significantly over time. Early systems were based on the RealityEngine, Geometry Engine that Clark and Marc Hannah had developed at Stanford University, and were derived from Clark's broader background in computer graphics. The Geometry Engine was the first very-large-scale integration (VLSI) implementation of a geometry pipeline, specialized hardware that accelerated the "inner-loop" geometric computations needed to display three-dimensional ...
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NIS+
NIS+ is a directory service developed by Sun Microsystems to replace its older 'NIS' (Network Information Service). It is designed to eliminate the need for duplication across many computers of configuration data such as user accounts, host names and addresses, printer information and NFS disk mounts on individual systems, instead using a central repository on a master server, simplifying system administration. NIS+ client software has been ported to other Unix and Unix-like platforms. Prior to the release of Solaris 9 in 2002, Sun announced its intent to remove NIS+ from Solaris in a future release and now recommends that customers instead use an LDAP-based lookup scheme. NIS+ was present in Solaris 9 and 10 (although both releases include tools to migrate NIS+ data to an LDAP server) and it has been removed from Solaris 11. NIS vs. NIS+ NIS and NIS+ are similar only in purpose and name, otherwise, they are completely different implementations. They differ in the following ...
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Network Information Service
The Network Information Service, or NIS (originally called Yellow Pages or YP), is a client–server directory service protocol (computing), protocol for Distributed computing, distributing system configuration data such as User (computing), user and host names between computers on a computer network. Sun Microsystems developed the NIS; the technology is Software license, licensed to virtually all other Unix vendors. Because British Telecom PLC owned the name "Yellow Pages" as a registered trademark in the United Kingdom for its paper-based, commercial telephone directory, Sun changed the name of its system to NIS, though all the commands and functions still start with "yp". A NIS/YP system maintains and distributes a central directory of user and group information, hostnames, e-mail aliases and other text-based tables of information in a computer network. For example, in a common Unix, UNIX environment, the list of users for Identification (information), identification is placed ...
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Solaris (operating System)
Oracle Solaris is a proprietary software, proprietary Unix operating system offered by Oracle Corporation, Oracle for SPARC and x86-64 based workstations and server (computing), servers. Originally developed by Sun Microsystems as Solaris, it superseded the company's earlier SunOS in 1993 and became known for its scalability, especially on SPARC systems, and for originating many innovative features such as DTrace, ZFS and Time Slider. After the Acquisition of Sun Microsystems by Oracle Corporation, Sun acquisition by Oracle in 2010, it was renamed Oracle Solaris. Solaris was registered as compliant with the Single UNIX Specification until April 29, 2019. Historically, Solaris was developed as proprietary software. In June 2005, Sun Microsystems released most of the codebase under the CDDL license, and founded the OpenSolaris Open-source software, open-source project. Sun aimed to build a developer and user community with OpenSolaris; after the Oracle acquisition in 2010, the Open ...
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HP-UX
HP-UX (from "Hewlett Packard Unix") is a proprietary software, proprietary implementation of the Unix operating system developed by Hewlett Packard Enterprise; current versions support HPE Integrity Servers, based on Intel's Itanium architecture. It is based on Unix System V (initially Unix System III, System III) and first released in 1984. Earlier versions of HP-UX supported the HP Integral PC and HP 9000 Series 200, 300, and 400 computer systems based on the Motorola 68000 series of processors, the HP 9000 Series 500 computers based on HP's proprietary HP FOCUS, FOCUS architecture, and later HP 9000 Series models based on HP's PA-RISC instruction set architecture. HP-UX was the first Unix to offer access-control lists for file access permissions as an alternative to the standard Unix permissions system. HP-UX was also among the first Unix systems to include a built-in logical volume management, logical volume manager. HP has had a long partnership with Veritas Software, a ...
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IBM AIX
AIX (pronounced ) is a series of Proprietary software, proprietary Unix operating systems developed and sold by IBM since 1986. The name stands for "Advanced Interactive eXecutive". Current versions are designed to work with Power ISA based Server (computing), server and workstation computers such as IBM's IBM Power Systems, Power line. Background Originally released for the IBM RT PC Reduced instruction set computer, RISC workstation in 1986, AIX has supported a wide range of hardware platforms, including the IBM IBM RS/6000, RS/6000 series and later IBM Power microprocessors, Power and PowerPC-based systems, IBM System i, System/370 mainframes, IBM PS/2, PS/2 personal computers, and the Apple Network Server. Currently, it is supported on IBM Power Systems alongside IBM i and Linux. AIX is based on UNIX System V with 4.3BSD-compatible extensions. It is certified to the UNIX 03 and UNIX V7 specifications of the Single UNIX Specification, beginning with AIX versions 5.3 an ...
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Passwd
passwd is a command on Unix, Plan 9, Inferno, and most Unix-like operating systems used to change a user's password. The password entered by the user is run through a key derivation function to create a hashed version of the new password, which is saved. Only the hashed version is stored; the entered password is not saved for security reasons. When the user logs on, the password entered by the user during the log on process is run through the same key derivation function and the resulting hashed version is compared with the saved version. If the hashes are identical, the entered password is considered to be correct, and the user is authenticated. In theory, it is possible for two different passwords to produce the same hash. However, cryptographic hash functions are designed in such a way that finding any password that produces the same hash is very difficult and practically infeasible, so if the produced hash matches the stored one, the user can be authenticated. The passw ...
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SVr4
Unix System V (pronounced: "System Five") is one of the first commercial versions of the Unix operating system. It was originally developed by AT&T and first released in 1983. Four major versions of System V were released, numbered 1, 2, 3, and 4. System V Release 4 (SVR4) was commercially the most successful version, being the result of an effort, marketed as ''Unix System Unification'', which solicited the collaboration of the major Unix vendors. It was the source of several common commercial Unix features. System V is sometimes abbreviated to SysV. , the AT&T-derived Unix market is divided between four System V variants: IBM's AIX, Hewlett Packard Enterprise's HP-UX and Oracle's Solaris, plus the free-software illumos forked from OpenSolaris. Overview Introduction System V was the successor to 1982's UNIX System III. While AT&T developed and sold hardware that ran System V, most customers ran a version from a reseller, based on AT&T's reference implementation. A s ...
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