Command, in computer science, an instruction that initiates a computer function, operation, or program. All computer programs respond to some sort of specific commands, with more complicated programs generally having a larger quantity and variety of commands. Commands for similar functions differ depending on the computer system and operating system being used.
Commands are an integral part of the interface between the user and computer. Computers usually employ one of two types of user interfaces: command-line interfaces or graphical user interfaces (GUIs). Command-line interfaces are based on text. An example of a command-line interface is Microsoft Corporation’s Disk Operating System (MS-DOS). In programs that respond to commands through a command-line interface, the user must enter an exact command, usually in the form of a keyword, into the computer. An example is the command MEM in MS-DOS, which displays information about the amount and the various types of memory in the main computer memory.
Graphical user interfaces, such as the Apple Computer Inc. operating system and Microsoft’s Windows 95 operating system, enable the user to enter commands into the computer by single-or double-clicking a mouse button once an appropriate icon or keyword has been selected. The icon or keyword is selected from a menu, from the desktop, or from a window.
Once a user enters a command into the computer, the command is read by the computer’s operating system. The operating system is the most important program running on a computer because it performs basic functions, such as memory allocation, and allows other computer programs to run. One of the functions of the operating system is to interpret commands. This function is performed by a program running within each computer’s operating system called the command interpreter. The command interpreter reads the commands from the user or from a file and executes them.
Commands are an integral part of the interface between the user and computer. Computers usually employ one of two types of user interfaces: command-line interfaces or graphical user interfaces (GUIs). Command-line interfaces are based on text. An example of a command-line interface is Microsoft Corporation’s Disk Operating System (MS-DOS). In programs that respond to commands through a command-line interface, the user must enter an exact command, usually in the form of a keyword, into the computer. An example is the command MEM in MS-DOS, which displays information about the amount and the various types of memory in the main computer memory.
Graphical user interfaces, such as the Apple Computer Inc. operating system and Microsoft’s Windows 95 operating system, enable the user to enter commands into the computer by single-or double-clicking a mouse button once an appropriate icon or keyword has been selected. The icon or keyword is selected from a menu, from the desktop, or from a window.
Once a user enters a command into the computer, the command is read by the computer’s operating system. The operating system is the most important program running on a computer because it performs basic functions, such as memory allocation, and allows other computer programs to run. One of the functions of the operating system is to interpret commands. This function is performed by a program running within each computer’s operating system called the command interpreter. The command interpreter reads the commands from the user or from a file and executes them.
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