A "Hello, World!" program is a computer program that outputs or displays "Hello, World!" to a user.
The Apache HTTP Server, colloquially called Apache, is a free and open-source cross-platform web server, released under the terms of Apache License 2.0.
Language support for array types may include certain built-in array data types, some syntactic constructions (array type constructors) that the programmer may use to define such types and declare array variables, and special notation for indexing array elements.
In computer science, an associative array, map, symbol table, or dictionary is an abstract data type composed of a collection of (key, value) pairs, such that each possible key appears at most once in the collection.
In the Perl programming language, autovivification is the automatic creation of new arrays and hashes as required every time an undefined value is dereferenced.
Backtracking is a general algorithm for finding all (or some) solutions to some computational problems, notably constraint satisfaction problems, that incrementally builds candidates to the solutions, and abandons a candidate ("backtracks") as soon as it determines that the candidate cannot possibly be completed to a valid solution.
In computer science, a call stack is a stack data structure that stores information about the active subroutines of a computer program.
In computer programming, a comment is a programmer-readable explanation or annotation in the source code of a computer program.
A conditional operator is a type of operator.
The Comprehensive Perl Archive Network (CPAN) is a repository of over 250,000 software modules and accompanying documentation for 39,000 distributions, written in the Perl programming language by over 12,000 contributors.
In computer science and computer programming, a data type or simply type is a classification of data which tells the compiler or interpreter how the programmer intends to use the data.
In computing and telecommunication, an escape character is a character which invokes an alternative interpretation on subsequent characters in a character sequence.
In Unix and related computer operating systems, a file descriptor (FD, less frequently fildes) is an abstract indicator (handle) used to access a file or other input/output resource, such as a pipe or network socket.
A filename extension is an identifier specified as a suffix to the name of a computer file.
In computer science, functional programming is a programming paradigm—a style of building the structure and elements of computer programs—that treats computation as the evaluation of mathematical functions and avoids changing-state and mutable data.
In computer programming, glob patterns specify sets of filenames with wildcard characters.
In computing, a hash table (hash map) is a data structure that implements an associative array abstract data type, a structure that can map keys to values.
Henry Spencer (born 1955) is a Canadian computer programmer and space enthusiast.
In computing, a here document (here-document, here-text, heredoc, hereis, here-string or here-script) is a file literal or input stream literal: it is a section of a source code file that is treated as if it were a separate file.
In logic and related fields such as mathematics and philosophy, if and only if (shortened iff) is a biconditional logical connective between statements.
In computing, input/output or I/O (or, informally, io or IO) is the communication between an information processing system, such as a computer, and the outside world, possibly a human or another information processing system.
Java is a general-purpose computer-programming language that is concurrent, class-based, object-oriented, and specifically designed to have as few implementation dependencies as possible.
Microsoft Windows is a group of several graphical operating system families, all of which are developed, marketed, and sold by Microsoft.
In object-oriented programming languages, a Mixin is a class that contains methods for use by other classes without having to be the parent class of those other classes.
Moose is an extension of the object system of the Perl programming language.
Newline (frequently called line ending, end of line (EOL), line feed, or line break) is a control character or sequence of control characters in a character encoding specification, e.g. ASCII or EBCDIC.
Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which may contain data, in the form of fields, often known as attributes; and code, in the form of procedures, often known as methods. A feature of objects is that an object's procedures can access and often modify the data fields of the object with which they are associated (objects have a notion of "this" or "self").
In mathematics and computer programming, the order of operations (or operator precedence) is a collection of rules that reflect conventions about which procedures to perform first in order to evaluate a given mathematical expression.
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages, Perl 5 and Perl 6.
Perl 6 is a member of the Perl family of programming languages.
Perl Compatible Regular Expressions (PCRE) is a library written in C, which implements a regular expression engine, inspired by the capabilities of the Perl programming language.
PHP: Hypertext Preprocessor (or simply PHP) is a server-side scripting language designed for Web development, but also used as a general-purpose programming language.
In Unix-like computer operating systems, a pipeline is a sequence of processes chained together by their standard streams, so that the output of each process (stdout) feeds directly as input (stdin) to the next one.
The Portable Operating System Interface (POSIX) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems.
Programming paradigms are a way to classify programming languages based on their features.
In computer science, a reference is a value that enables a program to indirectly access a particular datum, such as a variable's value or a record, in the computer's memory or in some other storage device.
A regular expression, regex or regexp (sometimes called a rational expression) is, in theoretical computer science and formal language theory, a sequence of characters that define a search pattern.
Rounding a numerical value means replacing it by another value that is approximately equal but has a shorter, simpler, or more explicit representation; for example, replacing $ with $, or the fraction 312/937 with 1/3, or the expression with.
Ruby is a dynamic, interpreted, reflective, object-oriented, general-purpose programming language.
In computing, a shebang is the character sequence consisting of the characters number sign and exclamation mark at the beginning of a script.
Short-circuit evaluation, minimal evaluation, or McCarthy evaluation (after John McCarthy) is the semantics of some Boolean operators in some programming languages in which the second argument is executed or evaluated only if the first argument does not suffice to determine the value of the expression: when the first argument of the AND function evaluates to false, the overall value must be false; and when the first argument of the OR function evaluates to true, the overall value must be true.
In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable.
In computer programming, a subroutine is a sequence of program instructions that performs a specific task, packaged as a unit.
In computer programming languages, a switch statement is a type of selection control mechanism used to allow the value of a variable or expression to change the control flow of program execution via a multiway branch.
In computer science, a tail call is a subroutine call performed as the final action of a procedure.
There's more than one way to do it (TMTOWTDI or TIMTOWTDI, pronounced Tim Toady) is a Perl programming motto.
In programming languages, a type system is a set of rules that assigns a property called type to the various constructs of a computer program, such as variables, expressions, functions or modules.
In computer programming, a variable or scalar is a storage location (identified by a memory address) paired with an associated symbolic name (an identifier), which contains some known or unknown quantity of information referred to as a value.
.NET Framework (pronounced dot net) is a software framework developed by Microsoft that runs primarily on Microsoft Windows.