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Scsh
Scsh (a ''Scheme shell'') is computer software, a type of shell for an operating system. It is a Portable Operating System Interface (POSIX) application programming interface (API) layered on the programming language Scheme, in a manner to make the most of Scheme's ability for scripting. Scsh is limited to 32-bit platforms but there is a development version against the latest Scheme 48 that works in 64-bit mode. It is free and open-source software released under the BSD-3-Clause license. Features Scsh includes these notable features: * Library support for list, character, and string manipulations; * Regular expressions manipulation support using ''scheme regular expressions'', a domain-specific language (DSL), or little languages, approach to the abilities; * Strong networking support; * High-level support for awk like scripts, integrated into the language as macros; * Abstractions supporting pseudo terminals; * A shell language, modeled using quasi-quotation. Example * Pr ...
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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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Scheme 48
Scheme 48 is a programming language, a dialect of the language Scheme, an implementation using an interpreter which interprets bytecode. It has a foreign function interface for calling functions from the language C and comes with a library for regular expressions (regex), and an interface for Portable Operating System Interface (POSIX). It is supported by the portable Scheme library SLIB, and is the basis for the Scheme shell Scsh. It has been used in academic research. It is free and open-source software released under a BSD license. It is called "Scheme 48" because the first version was written in 48 hours in August 1986. The authors now say it is intended to be understood in 48 hours. Implementation Scheme 48 uses a virtual machine to interpret the bytecode Bytecode (also called portable code or p-code) is a form of instruction set designed for efficient execution by a software interpreter. Unlike human-readable source code, bytecodes are compact numeric codes, c ...
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String (computer Science)
In computer programming, a string is traditionally a sequence of character (computing), characters, either as a literal (computer programming), literal constant or as some kind of Variable (computer science), variable. The latter may allow its elements to be Immutable object, mutated and the length changed, or it may be fixed (after creation). A string is often implemented as an array data structure of bytes (or word (computer architecture), words) that stores a sequence of elements, typically characters, using some character encoding. More general, ''string'' may also denote a sequence (or List (abstract data type), list) of data other than just characters. Depending on the programming language and precise data type used, a variable (programming), variable declared to be a string may either cause storage in memory to be statically allocated for a predetermined maximum length or employ dynamic allocation to allow it to hold a variable number of elements. When a string appears lit ...
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Scheme (programming Language) Implementations
Scheme or schemer may refer to: Arts and entertainment * ''The Scheme'', a BBC Scotland documentary TV series * The Scheme (band), an English pop band * ''The Scheme'', an action role-playing video game for the PC-8801, made by Quest Corporation * Schemer (comics), Richard Fisk, a Marvel Comics villain turned antihero * Horace Schemer, a fictional character in the TV series '' Shining Time Station'' * ''Schemers'' (film), a Scottish film Computing * Scheme (programming language), a minimalist dialect of Lisp * Scheme (URI), the front part of a web link, like "http" or "ftp" * Google Schemer, a former service allowing its users to share plans and interests Other uses * Classification scheme (information science), eg a thesaurus, a taxonomy, a data model or an ontology * Scheme (mathematics), a concept in algebraic geometry * Scheme (rhetoric), a figure of speech that changes a sentence's structure * Scam, an attempt to swindle or cheat people through deception * Scheme, a type ...
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Scheme (programming Language) Interpreters
Scheme or schemer may refer to: Arts and entertainment * ''The Scheme'', a BBC Scotland documentary TV series * The Scheme (band), an English pop band * ''The Scheme'', an action role-playing video game for the PC-8801, made by Quest Corporation * Schemer (comics), Richard Fisk, a Marvel Comics villain turned antihero * Horace Schemer, a fictional character in the TV series '' Shining Time Station'' * ''Schemers'' (film), a Scottish film Computing * Scheme (programming language), a minimalist dialect of Lisp * Scheme (URI), the front part of a web link, like "http" or "ftp" * Google Schemer, a former service allowing its users to share plans and interests Other uses * Classification scheme (information science), eg a thesaurus, a taxonomy, a data model or an ontology * Scheme (mathematics), a concept in algebraic geometry * Scheme (rhetoric), a figure of speech that changes a sentence's structure * Scam, an attempt to swindle or cheat people through deception * Scheme, a ty ...
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Unix Shells
A Unix shell is a command-line interpreter or shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses Science Biology * Seashell, a hard outer layer of a marine ani ... 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 Wildcard character, wildcarding, Pipeline (Unix), piping, here documents, command substitution, Variable (programming), variables and control flow, control structures for Conditional (programming), condition-testing and iteration. ...
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Acknowledgment (creative Arts)
In the creative arts and scientific literature, an acknowledgment (British English also acknowledgement
is an expression of a gratitude for assistance in creating an original work. Receiving credit by way of acknowledgment rather than authorship indicates that the person or organization did not have a direct hand in producing the work in question, but may have contributed funding, criticism, or encouragement to the author(s). Various schemes exist for classifying acknowledgments; Cronin et al. give the following six categories: # # #
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Standard Output
Standard may refer to: Symbols * Colours, standards and guidons, kinds of military signs * Standard (emblem), a type of a large symbol or emblem used for identification Norms, conventions or requirements * Standard (metrology), an object that bears a defined relationship to a unit of measure used for calibration of measuring devices * Standard (timber unit), an obsolete measure of timber used in trade * Breed standard (also called bench standard), in animal fancy and animal husbandry * BioCompute Standard, a standard for next generation sequencing * ''De facto'' standard, product or system with market dominance * Gold standard, a monetary system based on gold; also used metaphorically for the best of several options, against which the others are measured * Internet Standard, a specification ratified as an open standard by the Internet Engineering Task Force * Learning standards, standards applied to education content * Standard displacement, a naval term describing th ...
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Environment Variable
An environment variable is a user-definable value that can affect the way running processes will behave on a computer. Environment variables are part of the environment in which a process runs. For example, a running process can query the value of the TEMP environment variable to discover a suitable location to store temporary files, or the HOME or USERPROFILE variable to find the directory structure owned by the user running the process. They were introduced in their modern form in 1979 with Version 7 Unix, so are included in all Unix operating system flavors and variants from that point onward including Linux and macOS. From PC DOS 2.0 in 1982, all succeeding Microsoft operating systems, including Microsoft Windows, and OS/2 also have included them as a feature, although with somewhat different syntax, usage and standard variable names. Design In all Unix and Unix-like systems, as well as on Windows, each process has its own separate set of environment vari ...
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Quasi-quotation
Quasi-quotation or Quine quotation is a linguistic device in formal languages that facilitates rigorous and terse formulation of general rules about linguistic expressions while properly observing the use–mention distinction. It was introduced by the philosopher and logician Willard Van Orman Quine in his book ''Mathematical Logic'', originally published in 1940. Put simply, quasi-quotation enables one to introduce symbols that ''stand for'' a linguistic expression in a given instance and are ''used as'' that linguistic expression in a different instance. For example, one can use quasi-quotation to illustrate an instance of substitutional quantification, like the following: ::"Snow is white" is true if and only if snow is white. ::Therefore, there is some sequence of symbols that makes the following sentence true when every instance of φ is replaced by that sequence of symbols: "φ" is true if and only if φ. Quasi-quotation is used to indicate (usually in more complex for ...
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Pseudo Terminal
In some operating systems, including Unix-like systems, a pseudoterminal, pseudotty, or PTY is a pair of pseudo-device endpoints (files) which establish an asynchronous, Duplex (telecommunications), bidirectional communication (IPC socket, IPC) channel (with two ports) between two or more processes. One pseudo-device in the pair, the ''master'', provides means by which a terminal emulator or remote login server (e.g. a Telnet, Berkeley r-commands, rlogin, or Secure Shell server) computer process, process controls the slave. The other pseudo-device, the ''slave'', emulates a hardware serial port device, and is used by terminal-oriented programs such as shells (e.g. Bash (Unix shell), bash) as a processes to read/write data back from/to ''master'' endpoint. PTYs are similar to bidirectional pipes. Devpts is a Linux kernel virtual file system containing pseudoterminal devices. Linux implementation is based on UNIX System V, System V-style terminals (commonly referred as UNIX 98 pse ...
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Macro (computer Science)
In computer programming, a macro (short for "macro instruction"; ) is a rule or pattern that specifies how a certain input should be mapped to a replacement output. Applying a macro to an input is known as macro expansion. The input and output may be a sequence of lexical tokens or characters, or a syntax tree. Character macros are supported in software applications to make it easy to invoke common command sequences. Token and tree macros are supported in some programming languages to enable code reuse or to extend the language, sometimes for domain-specific languages. Macros are used to make a sequence of computing instructions available to the programmer as a single program statement, making the programming task less tedious and less error-prone. Thus, they are called "macros" because a "big" block of code can be expanded from a "small" sequence of characters. Macros often allow positional or keyword parameters that dictate what the conditional assembler program gen ...
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