词条 | Command (computing) |
释义 |
In computing, a command is a directive to a computer program acting as an interpreter of some kind to perform a specific task. Most commonly a command is either a directive to some kind of command-line interface, such as a shell, or an event in a graphical user interface triggered by the user selecting an option in a menu. 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. Many programs allow specially formatted arguments, known as flags or options, 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. ExamplesHere are some commands given to a command-line interpreter (Unix shell). The following command changes the user's place in the directory tree from their current position to the directory {{Mono|/home/pete}}. The command is The following command prints the text Hello World out to the standard output stream, which, in this case, will just print the text out on the screen. The command is The following commands are equivalent. They list files in the directory {{Mono|/bin}}. The command is The following command displays the contents of the files {{Mono|ch1.txt}} and {{Mono|ch2.txt}}. The command is Here are some commands given to a different command-line interpreter (the DOS, OS/2 and Microsoft Windows command prompt). Notice that the flags are identified differently but that the concepts are the same: The following command displays the contents of the file {{Mono|readme.txt}}. The command is The following command lists all the contents of the current directory. The command is See also
External links{{Wikibooks|Guide to Windows commands}}
References1. ^{{cite web | url = https://ss64.com/nt/type.html | accessdate = 14 March 2019 | title = Type - Display a text file - Windows CMD | publisher = SS64.com }} 2. ^{{cite web | url = https://ss64.com/nt/dir.html | accessdate = 14 March 2019 | title = DIR - list files and folders - Windows CMD | publisher = SS64.com }} 3 : User interfaces|Computing terminology|Computing commands |
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