In computing, a command is a directive to a computer program acting as an interpreter of some kind, in order to perform a specific task. Most commonly a command is a directive to some kind of command line interface, such as a shell. RAM (Random Access Memory) Look up computing in Wiktionary, the free dictionary. ... This article or section does not adequately cite its references or sources. ...

Specifically, the term command is used in imperative computer languages. These languages are called this, because statements in these languages are usually written in a manner similar to the imperative mood used in many natural languages. If one views a statement in an imperative language as being like a sentence in a natural language, then a command is generally like a verb in such a language. In computer science, imperative programming, as opposed to declarative programming, is a programming paradigm that describes computation in terms of a program state and statements that change the program state. ... The term computer language is a more expansive and alternate term for the more commonly-used term programming language. ... A statement is the minimal unit of structuring in imperative programming languages. ... In linguistics, many grammars have the concept of grammatical mood, which describes the relationship of a verb with reality and intent. ... The term natural language is used to distinguish languages spoken and signed (by hand signals and facial expressions) by humans for general-purpose communication from constructs such as writing, computer-programming languages or the languages used in the study of formal logic, especially mathematical logic. ... In computer science, imperative programming, as opposed to declarative programming, is a programming paradigm that describes computation in terms of a program state and statements that change the program state. ...

Many programs allow specially formatted arguments, known as flags, which modify the default behaviour of the command, while further arguments describe what the command acts on. Comparing to a natural language: the flags are adverbs, whilst the other arguments are objects. The factual accuracy of this article is disputed. ... An object in grammar is a sentence element and part of the sentence predicate. ...

Examples

Here are some commands given to a command line interpreter (Unix shell): It has been suggested that this article or section be merged into Command line interface. ... Screenshot of a sample Bash session, taken on Gentoo Linux. ...

• cd /home/pete

This command changes the user's place in the directory tree from their current position to the directory /home/pete. "cd" is the command and "/home/pete" is the argument.

• echo "Hello World"

This command prints the text hello out to the standard output stream, which, in this case, will just print the text out on the screen. "echo" is the command and ""Hello World"" is the argument. The quotes are used to prevent "Hello" and "World" being treated as separate arguments.

• ls -l -t -r /bin
• ls -ltr /bin

These commands are equivalent. They list files in the directory /bin. "ls" is the command, "/bin" is the argument and there are three flags: "l", "t" and "r".

• cat ch1.txt ch2.txt

This displays the coontents of the files ch1.txt and ch2.txt. "cat" is the command and "ch1.txt" and "ch2.txt" are both arguments.

Here are some commands given to a different command line interpreter (the Microsoft Windows and MS-DOS command prompt). Notice that the flags are identified differently but that the concepts are the same: The title given to this article is incorrect due to technical limitations. ... In computing, a directory, catalog, or folder[1] is an entity in a file system which contains a group of files and/or other directories. ... echo is a command in Unix (and by extension, its descendants, such as Linux) and MS-DOS that places a string on the terminal. ... The standard streams are a set of input and output channels featured in Unix and Unix-like operating systems, and provided by the standard I/O library (stdio. ... For other uses, see LS. ls is a command specified by POSIX and the Single UNIX Specification, and is thus implemented in Unix and Unix-like operating systems. ... The Filesystem Hierarchy Standard (FHS) defines the main directories and their contents in GNU/Linux and other Unix-like computer operating systems. ... For other uses, see LS. ls is a command specified by POSIX and the Single UNIX Specification, and is thus implemented in Unix and Unix-like operating systems. ... The Filesystem Hierarchy Standard (FHS) defines the main directories and their contents in GNU/Linux and other Unix-like computer operating systems. ... The title given to this article is incorrect due to technical limitations. ... To meet Wikipedias quality standards, the lead section of this article may need to be expanded. ... Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ...

• DIR /A

This lists all the contents of the current directory. "DIR" is the command and "A" is a flag. There is no argument.

• TYPE /P readme.txt

This displays the contents of the file readme.txt. "TYPE" is the command. "readme.txt" is the argument. "P" is a parameter.

In computer software, specifically the command line interface (CLI) of the DOS operating system, dir is a command used for file and directory listing. ... A partial list of the most common commands for Microsofts MS-DOS operating system follows. ...

See also

Wikibooks has more about this subject:

Guide to Windows commands

• List of Unix programs
• List of DOS commands
• Formal grammar