command line interface (CLI)

A command line interface (CLI) is a text-based user interface (UI) used to view and manage computer files. Command line interfaces are also called command-line user interfaces, console user interfaces and character user interfaces.

History and features of CLI:

Before the mouse, users interacted with an operating system (OS) or application with a keyboard. Users typed commands in the command line interface to run tasks on a computer.

Typically, the command line interface features a black box with white text. The user responds to a prompt in the command line interface by typing a command. The output or response from the system can include a message, table, list, or some other confirmation of a system or application action.

Today, most users prefer the graphical user interface (GUI) offered by operating systems such as Windows, Linux, and macOS. Most current Unix-based systems offer both a command line interface and a graphical user interface.

The MS-DOS operating system and the command shell in the Windows operating system are examples of command line interfaces. In addition, programming languages can support command line interfaces, such as Python.

Prompts and commands:

There are hundreds of different commands available in a command line. The set of commands may vary dramatically between operating systems or applications.

The following is a list of commands in the Microsoft task configuration and automation framework PowerShell:

• Get-Date: Retrieves the current time and date.

• cd: Used to change directories.

• Stop-Process: Terminates one or more system processes.

Although some commands operate alone, others require the use of arguments. The argument follows the command and provides additional details or specifics. For example, the cd command tells the OS to change to a different directory, but the command line must include the name of the desired directory path, as well.

For example, a full command with an argument appears as:

cd \documents\user

The arguments used with commands can also be extremely complex and granular. For example, the following command line string shows the PowerShell syntax to retrieve detailed network configuration information from a Windows machine:

Get-NetIPAddress | Sort InterfaceIndex | FT InterfaceIndex, InterfaceAlias, AddressFamily, IPAddress, PrefixLength -Autosize

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