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Backquotes
The backtick is a typographical mark used mainly in computing. It is also known as backquote, grave, or grave accent. The character was designed for typewriters to add a grave accent to a (lower-case) base letter, by overtyping it atop that letter. On early computer systems, however, this physical dead key+overtype function was rarely supported, being functionally replaced by precomposed characters. Consequently, this ASCII symbol was rarely (if ever) used in computer systems for its original aim and became repurposed for many unrelated uses in computer programming. The sign is located on the left-top of a US or UK layout keyboard, next to the key. On older keyboards the Escape key was at this location, and the backtick key was somewhere on the right side of the layout. Provision (if any) of the backtick on other keyboards varies by national keyboard layout and keyboard mapping. History Typewriters On typewriters designed for languages that routinely use diacritics (accent m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Command Substitution
In computing, command substitution is a facility that allows a command to be run and its output to be pasted back on the command line as arguments to another command. Command substitution first appeared in the Bourne shell, introduced with Version 7 Unix in 1979, and has remained a characteristic of all later Unix shells. The feature has since been adopted in other programming languages as well, including Perl, PHP, Ruby and Microsoft's Powershell under Windows. It also appears in Microsoft's CMD.EXE in the FOR command and the ( ) command. Syntax and semantics Shells typically implement command substitution by creating a child process to run the first command with its standard output piped back to the shell, which reads that output, parsing it into words separated by whitespace. Because the shell can't know it has all the output from the child until the pipe closes or the child dies, it waits until then before it starts another child process to run the second command. This C s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, engineering, mathematical, technological and social aspects. Major computing disciplines include computer engineering, computer science, cybersecurity, data science, information systems, information technology and software engineering. The term "computing" is also synonymous with counting and calculating. In earlier times, it was used in reference to the action performed by mechanical computing machines, and before that, to human computers. History The history of computing is longer than the history of computing hardware and includes the history of methods intended for pen and paper (or for chalk and slate) with or without the aid of tables. Computing is intimately tied to the representation of numbers, though mathematical conc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micro-
''Micro'' (Greek letter μ ( U+03BC) or the legacy symbol µ (U+00B5)) is a unit prefix in the metric system denoting a factor of 10−6 (one millionth). Confirmed in 1960, the prefix comes from the Greek ('), meaning "small". The symbol for the prefix is the Greek letter μ ( mu). It is the only SI prefix which uses a character not from the Latin alphabet. "mc" is commonly used as a prefix when the character "μ" is not available; for example, "mcg" commonly denotes a microgram. This may be ambiguous in rare circumstances in that ''mcg'' could also be read as a ''micrigram'', i.e. 10−14 g; however the prefix '' micri'' is not standard, nor widely known, and is considered obsolete. The letter u, instead of μ, was allowed by an ISO document, but that document has been withdrawn in 2001, however DIN 66030:2002 still allows this substitution. Examples * Typical bacteria are 1 to 10 micrometres (1–10 µm) in diameter. * Eukaryotic cells are typically 10 to 100 micrometre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julia (programming Language)
Julia is a high-level, dynamic programming language. Its features are well suited for numerical analysis and computational science. Distinctive aspects of Julia's design include a type system with parametric polymorphism in a dynamic programming language; with multiple dispatch as its core programming paradigm. Julia supports concurrent, (composable) parallel and distributed computing (with or without using MPI or the built-in corresponding to "OpenMP-style" threads), and direct calling of C and Fortran libraries without glue code. Julia uses a just-in-time (JIT) compiler that is referred to as "just- ahead-of-time" (JAOT) in the Julia community, as Julia compiles all code (by default) to machine code before running it. Julia is garbage-collected, uses eager evaluation, and includes efficient libraries for floating-point calculations, linear algebra, random number generation, and regular expression matching. Many libraries are available, including some (e.g., for fast Fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruby (programming Language)
Ruby is an interpreted, high-level, general-purpose programming language which supports multiple programming paradigms. It was designed with an emphasis on programming productivity and simplicity. In Ruby, everything is an object, including primitive data types. It was developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan. Ruby is dynamically typed and uses garbage collection and just-in-time compilation. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming. According to the creator, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, BASIC, Java and Lisp. History Early concept Matsumoto has said that Ruby was conceived in 1993. In a 1999 post to the ''ruby-talk'' mailing list, he describes some of his early ideas about the language: Matsumoto describes the design of Ruby as being like a simple Lisp language at its core, with an object system like that of Smalltalk, blocks inspired by higher-o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perl
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was officially changed to Raku in October 2019. Though Perl is not officially an acronym, there are various backronyms in use, including "Practical Extraction and Reporting Language". Perl was developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions. Raku, which began as a redesign of Perl 5 in 2000, eventually evolved into a separate language. Both languages continue to be developed independently by different development teams and liberally borrow ideas from each other. The Perl languages borrow features from other programming languages including C, sh, AWK, and sed; They provide text processing facilities without the arbitrary data-le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scripting Languages
A scripting language or script language is a programming language that is used to manipulate, customize, and automate the facilities of an existing system. Scripting languages are usually interpreted at runtime rather than compiled. A scripting language's primitives are usually elementary tasks or API calls, and the scripting language allows them to be combined into more programs. Environments that can be automated through scripting include application software, text editors, web pages, operating system shells, embedded systems, and computer games. A scripting language can be viewed as a domain-specific language for a particular environment; in the case of scripting an application, it is also known as an extension language. Scripting languages are also sometimes referred to as very high-level programming languages, as they sometimes operate at a high level of abstraction, or as control languages, particularly for job control languages on mainframes. The term ''scripting lang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Programming Languages By Type
This is a list of notable programming languages, grouped by type. There is no overarching classification scheme for programming languages. Thus, in many cases, a language is listed under multiple headings (in this regard, see " Multiparadigm languages" below). Array languages Array programming (also termed ''vector'' or ''multidimensional'') languages generalize operations on scalars to apply transparently to vectors, matrices, and higher-dimensional arrays. * A+ * Analytica * APL * BQN * Chapel * Fortran 90 * FreeMat * GAUSS * Interactive Data Language (IDL) * J * Julia * K * MATLAB * Octave * Q * R * S * Scilab * S-Lang * SequenceL * Speakeasy * Wolfram Language * X10 * ZPL Assembly languages Assembly languages directly correspond to a machine language (see below), so machine code instructions appear in a form understandable by humans, although there may not be a one-to-one mapping between an individual statement and an individual instruction. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free Software Foundation
The Free Software Foundation (FSF) is a 501(c)#501(c)(3), 501(c)(3) non-profit organization founded by Richard Stallman on October 4, 1985, to support the free software movement, with the organization's preference for software being distributed under copyleft ("share alike") terms, such as with its own GNU General Public License. The FSF was incorporated in Boston, Massachusetts, United States, US, where it is also based. From its founding until the mid-1990s, FSF's funds were mostly used to employ software developers to write free software for the GNU Project. Since the mid-1990s, the FSF's employees and volunteers have mostly worked on legal and structural issues for the free software movement and the free software community. Consistent with its goals, the FSF aims to use only free software on its own computers. History The Free Software Foundation was founded in 1985 as a Nonprofit corporation, non-profit corporation supporting free software development. It continued existi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Man Pages
A man page (short for manual page) is a form of software documentation usually found on a Unix or Unix-like operating system. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts. A user may invoke a man page by issuing the man command. By default, man typically uses a terminal pager program such as more or less to display its output. Man pages are often referred to as an ''on-line'' or ''online'' form of software documentation, * even though the man command does not require internet access, dating back to the times when printed ''out-of-band'' manuals were the norm. History In the first two years of the history of Unix, no documentation existed. The Unix Programmer's Manual' was first published on November 3, 1971. The first actual man pages were written by Dennis Ritchie and Ken Thompson at the insistence of their manager Doug McIlroy in 1971. Aside from the man pages, the ''Programmer' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extended ASCII
Extended ASCII is a repertoire of character encodings that include (most of) the original 96 ASCII character set, plus up to 128 additional characters. There is no formal definition of "extended ASCII", and even use of the term is sometimes criticized, because it can be mistakenly interpreted to mean that the American National Standards Institute (ANSI) had updated its standard to include more characters, or that the term identifies a single unambiguous encoding, neither of which is the case. The ISO standard ISO 8859 was the first international standard to formalise a (limited) expansion of the ASCII character set: of the many language variants it encoded, ISO 8859-1 ("ISO Latin 1")which supports most Western European languages is best known in the West. There are many other extended ASCII encodings (more than 220 DOS and Windows codepages). EBCDIC ("the other" major character code) likewise developed many extended variants (more than 186 EBCDIC codepages) over the decades. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Code Page 1013 ...
Code page 1013 (CCSID 1013), also known as CP1013, is the code page for the United Kingdom version of ISO 646 ( ISO 646-GB / IR-4), specified in BS 4730. Code page layout See also * Code page 1101 (similar DEC NRCS code page) References {{Character encoding 1013 Year in topic Year 1013 ( MXIII) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. Events By place Europe * King Henry II of Germany signs a peace treaty at Merseburg with Duke Boles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
