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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 * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of Command Shells
A command shell is a command-line interface to interact with and manipulate a computer's operating system. General characteristics Interactive features Background execution Background execution allows a shell to run a command without user interaction in the terminal, freeing the command line for additional work with the shell. POSIX shells and other Unix shells allow background execution by using the ''&'' character at the end of command. In PowerShell, the Start-Process or Start-Job cmdlets can be used. Completions Completion features assist the user in typing commands at the command line, by looking for and suggesting matching words for incomplete ones. Completion is generally requested by pressing the completion key (often the key). ''Command name completion'' is the completion of the name of a command. In most shells, a command can be a program in the command path (usually $PATH), a builtin command, a function or alias. ''Path completion'' is the completion of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix Shell
A Unix shell is a command-line Interpreter (computing), interpreter or shell (computing), 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 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. 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 environm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix Shells
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 interpreter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scheme 48
Scheme 48 is a programming language, a dialect of the language Scheme, an implementation using an interpreter which emits 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, cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
String (computer Science)
In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. The latter may allow its elements to be mutated and the length changed, or it may be fixed (after creation). A string is generally considered as a data type and is often implemented as an array data structure of bytes (or words) that stores a sequence of elements, typically characters, using some character encoding. ''String'' may also denote more general arrays or other sequence (or list) data types and structures. Depending on the programming language and precise data type used, a 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 literally in source code, it is known as a string literal or an anonymous string. In formal languages, which are used in mathematical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scheme (programming Language) Implementations
A scheme is a systematic plan for the implementation of a certain idea. Scheme or schemer may refer to: Arts and entertainment * ''The Scheme'' (TV series), a BBC Scotland documentary 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'' * Schemee, a fictional child character and Schemer's nephew in the TV Series ''Shining Time Station'' * ''Schemers'' (film), a Scottish film Other uses * Classification scheme, eg a thesaurus, a taxonomy, a data model, or an ontology * Scheme (programming language), a minimalist dialect of Lisp * Scheme (mathematics), a concept in algebraic geometry * Scheme (linguistics), a figure of speech that changes a sentence's structure * Scam, an attempt to swindle or cheat people through deception **Get-rich-qu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scheme (programming Language) Interpreters
A scheme is a systematic plan for the implementation of a certain idea. Scheme or schemer may refer to: Arts and entertainment * ''The Scheme'' (TV series), a BBC Scotland documentary 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'' * Schemee, a fictional child character and Schemer's nephew in the TV Series ''Shining Time Station'' * ''Schemers'' (film), a Scottish film Other uses * Classification scheme, eg a thesaurus, a taxonomy, a data model, or an ontology * Scheme (programming language), a minimalist dialect of Lisp * Scheme (mathematics), a concept in algebraic geometry * Scheme (linguistics), a figure of speech that changes a sentence's structure * Scam, an attempt to swindle or cheat people through deception **Get-rich-quick ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acknowledgment (creative Arts)
In the creative arts and scientific literature, an acknowledgement (also spelled acknowledgment in American and Canadian English) is an expression of a gratitude for assistance in creating an original work. Receiving credit by way of acknowledgement 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 acknowledgements; Cronin et al. give the following six categories: # moral support # financial support # editorial support # presentational support # instrumental/technical support # conceptual support, or peer interactive communication (PIC) Apart from citation, which is not usually considered to be an acknowledgement, acknowledgement of conceptual support is widely considered to be the most important for identifying intellectual debt. Some acknowledgements of financial support, on the oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Output
In computer programming, standard streams are interconnected input and output communication channels between a computer program and its environment when it begins execution. The three input/output (I/O) connections are called standard input (stdin), standard output (stdout) and standard error (stderr). Originally I/O happened via a physically connected system console (input via keyboard, output via monitor), but standard streams abstract this. When a command is executed via an interactive shell, the streams are typically connected to the text terminal on which the shell is running, but can be changed with redirection or a pipeline. More generally, a child process inherits the standard streams of its parent process. Application Users generally know standard streams as input and output channels that handle data coming from an input device, or that write data from the application. The data may be text with any encoding, or binary data. In many modern systems, the standard error str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environment Variable
An environment variable is a dynamic-named value that can affect the way running processes will behave on a computer. They 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 variables. By default, when a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudo Terminal
In some operating systems, including Unix and Linux, a pseudoterminal, pseudotty, or PTY is a pair of pseudo-device endpoints (files) which establish asynchronous, bidirectional communication ( IPC) channel (with two ports) between two or more processes. The ''master'' provides means by which a terminal emulator process controls the slave. The ''slave'', emulates a hardware text terminal device. PTY are similar to bidirectional pipes. The ''master'' files are typically used by networking applications (e.g. rlogin) and ''slave'' files are used by terminal-oriented programs such as shells (e.g. bash) as a processes to read/write data back from/to ''master'' endpoint. Common application of PTYs is in providing network login services. Devpts is a Linux Kernel virtual file system used to emulate PTYs connection. Linux implementation is based on System V-style terminals (commonly referred as UNIX 98 pseudoterminals) and provides POSIX and the Single Unix Specification API in the form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
