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Clear (Unix)
is a computer operating system command which is used to bring the command line on top of the computer terminal. It is available in various Unix shells on Unix and Unix-like operating systems as well as on other systems such as KolibriOS. Depending on the system, clear uses the terminfo or termcap database, as well as looking into the environment for the terminal type in order to deduce how to clear the screen. The Unix command clear takes no arguments and is roughly analogous to the command cls on a number of other operating systems. In ISO 9995-7 specifies that the following symbol be used to indicate this function on a keyboard, which is included in Unicode as: ⎚ CLEAR SCREEN SYMBOL. One may use the reset command to erase every previous command. History The clear command appeared in 2.79BSD The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Systems Research Group
The Computer Systems Research Group (CSRG) was a research group at the University of California, Berkeley that was dedicated to enhancing AT&T Unix operating system and funded by Defense Advanced Research Projects Agency. History Professor Bob Fabry of Berkeley acquired a UNIX source license from AT&T in 1974. His group started to modify UNIX, and distributed their version as the Berkeley Software Distribution (BSD). In April 1980, Fabry signed a contract with DARPA to develop UNIX even further and accommodate the specific requirements of the ARPAnet. With this funding, Fabry created the Computer Systems Research Group. The Berkeley Sockets API and Berkeley Fast File System are some of the group's most significant innovations. The sockets interface solved the problem of supporting multiple protocols (e.g. XNS and TCP/IP), and extended UNIX's "everything is a file" notion to these network protocols, while the Fast File System increased the block allocation size from 512 byte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix Shell
A Unix shell is a command-line interpreter or shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command language and a scripting language, and is used by the operating system to control the execution of the system using shell scripts. Users typically interact with a Unix shell using a terminal emulator; however, direct operation via serial hardware connections or Secure Shell are common for server systems. All Unix shells provide filename wildcarding, piping, here documents, command substitution, variables and control structures for condition-testing and iteration. Concept Generally, a ''shell'' is a program that executes other programs in response to text commands. A sophisticated shell can also change the environment in which other programs execute by passing named variables, a parameter list, or an input source. In Unix-like operating systems, users typically have many choices of command-line in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Unix Commands
This is a list of Unix commands as specified by IEEE Std 1003.1-2008, which is part of the Single UNIX Specification (SUS). These commands can be found on Unix operating systems and most Unix-like operating systems. List See also * List of GNU Core Utilities commands * List of GNOME applications * List of GNU packages * List of KDE applications * List of Unix daemons This is a list of Unix daemons that are found on various Unix-like operating systems. Unix daemons typically have a name ending with a ''d''. See also *List of Unix commands This is a list of Unix commands as specified by IEEE Std 1003.1- ... * List of web browsers for Unix and Unix-like operating systems * Unix philosophy * Footnotes External links IEEE Std 1003.1,2004 specificationsIEEE Std 1003.1,2008 specifications– configurable list of equivalent programs for *nix systems. – explains the names of many Unix commands. {{Unix commands Unix programs System administration [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Version 8 Unix
The term "Research Unix" refers to 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). History The term ''Research Unix'' first appeared in the Bell System Technical Journal (Vol. 57, No. 6, Pt. 2 Jul/Aug 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. However, that term was little-used until Version 8 Unix, but has been retroactively applied to earlier versions as well. Prior to V8, the operating system was most commonly called simply UNIX (in caps) or the UNIX Time-Sharing System. AT&T licensed Version 5 to educational institutions, and Version 6 also to commercial sites. Schools paid $200 and others $20,000, discouraging most commercial use, but Version 6 was the most widely used version into the 1980s. Research Unix versions are often refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reset (computing)
In a computer or data transmission system, a reset clears any pending errors or events and brings a system to normal condition or an initial state, usually in a controlled manner. It is usually done in response to an error condition when it is impossible or undesirable for a processing activity to proceed and all error recovery mechanisms fail. A computer storage program would normally perform a "reset" if a command times out and error recovery schemes like retry or abort also fail. Most computers have a reset line that brings the device into the startup state and is active for a short time after powering on. For example, in the x86 architecture, asserting the RESET line halts the CPU; this is done after the system is switched on and before the power supply has asserted "power good" to indicate that it is ready to supply stable voltages at sufficient power levels. Reset places less stress on the hardware than power cycling, as the power is not removed. Many computers, especial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unicode
Unicode, formally The Unicode Standard,The formal version reference is is an information technology standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard, which is maintained by the Unicode Consortium, defines as of the current version (15.0) 149,186 characters covering 161 modern and historic scripts, as well as symbols, emoji (including in colors), and non-visual control and formatting codes. Unicode's success at unifying character sets has led to its widespread and predominant use in the internationalization and localization of computer software. The standard has been implemented in many recent technologies, including modern operating systems, XML, and most modern programming languages. The Unicode character repertoire is synchronized with Universal Coded Character Set, ISO/IEC 10646, each being code-for-code identical with the other. ''The Unicode Standard'', however, includes more th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cls (computing)
In computing, CLS (for clear screen) is a command used by the command-line interpreters COMMAND.COM and cmd.exe on DOS, Digital Research FlexOS, IBM OS/2, Microsoft Windows and ReactOS operating systems to clear the screen or console window of commands and any output generated by them. It does not clear the user's history of commands, however. The command is also available in the DEC RT-11 operating system, in the open-source MS-DOS emulator DOSBox and in the EFI shell. In other environments, such as Linux and Unix, the same functionality is provided by the clear command. History The command is available in MS-DOS versions 2 and later. While the ultimate origins of using the three-character string CLS as the command to clear the screen likely predate Microsoft's use, this command was present before its MS-DOS usage, in the embedded ROM BASIC dialects Microsoft wrote for early 8-bit microcomputers (such as TRS-80 Color BASIC), where it served the same purpose. The MS-DOS dia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix Command
This is a list of Unix commands as specified by IEEE Std 1003.1-2008, which is part of the Single UNIX Specification (SUS). These commands can be found on Unix operating systems and most Unix-like operating systems. List See also * List of GNU Core Utilities commands * List of GNOME applications * List of GNU packages * List of KDE applications * List of Unix daemons * List of web browsers for Unix and Unix-like operating systems * Unix philosophy The Unix philosophy, originated by Ken Thompson, is a set of cultural norms and philosophical approaches to minimalist, modular software development. It is based on the experience of leading developers of the Unix operating system. Early Unix d ... * Footnotes External links IEEE Std 1003.1,2004 specificationsIEEE Std 1003.1,2008 specifications– configurable list of equivalent programs for *nix systems. – explains the names of many Unix commands. {{Unix commands Unix programs System administration ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spans formal techniques and practical considerations, including data modeling, efficient data representation and storage, query languages, security and privacy of sensitive data, and distributed computing issues, including supporting concurrent access and fault tolerance. A database management system (DBMS) is the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS software additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a database system. Often the term "database" is also used loosely to refer to any of the DBMS, the database system or an appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Termcap
Termcap (''terminal capability'') is a software library and database used on Unix-like computers. It enables programs to use display computer terminals in a device-independent manner, which greatly simplifies the process of writing portable text mode applications. Bill Joy wrote the first termcap library in 1978 for the Berkeley Unix operating system; it has since been ported to most Unix and Unix-like environments, even OS-9. Joy's design was reportedly influenced by the design of the terminal data store in the earlier Incompatible Timesharing System. A termcap database can describe the capabilities of hundreds of different display terminals. This allows programs to have character-based display output, independent of the type of terminal. On-screen text editors such as vi and emacs are examples of programs that may use termcap. Other programs are listed in the Termcap category. Examples of what the database describes: *how many columns wide the display is *what string to s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terminfo
Terminfo is a library and database that enables programs to use display terminals in a device-independent manner. Mary Ann Horton implemented the first terminfo library in 1981–1982 as an improvement over termcap. The improvements include * faster access to stored terminal descriptions, * longer, more understandable names for terminal capabilities and * general expression evaluation for strings sent to the terminal. Terminfo was included with UNIX System V Release 2 and soon became the preferred form of terminal descriptions in System V, rather than termcap (which BSD continued to use). This was imitated in pcurses in 1982–1984 by Pavel Curtis, and was available on other UNIX implementations, adapting or incorporating fixes from Mary Horton. For more information, refer to the posting on the comp.sources.unix newsgroup from December 1986. A terminfo database can describe the capabilities of hundreds of different display terminals. This allows external programs to be able to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Terminal
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and predated the use of a computer screen by decades. Early terminals were inexpensive devices but very slow compared to punched cards or paper tape for input, yet as the technology improved and video displays were introduced, terminals pushed these older forms of interaction from the industry. A related development was time-sharing systems, which evolved in parallel and made up for any inefficiencies in the user's typing ability with the ability to support multiple users on the same machine, each at their own terminal or terminals. The function of a terminal is typically confined to transcription and input of data; a device with significant local, programmable data-processing capability may be called a "smart terminal" or fat client. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
