Command Line Interface: Definition, Types & How It Works

What is Command Line Interface?

Command Line Interface, commonly known as CLI, is a user interface on a computer or operating system that allows users to interact with the system through a text command line.

In the Command Line Interface, users can enter text commands directly into the terminal or command prompt to perform tasks or manage the system.

Unlike a graphical user interface (GUI) that uses icons, menus, and other visual elements, CLI solely relies on simple text as the communication medium.

This user interface has been used since the early days of computer development and has become an integral part of modern operating systems.

How CLI Works

After understanding what CLI is, you need to grasp how it works. Essentially, this user interface involves the interaction concept between the user and the system through a text command line.

Here are the common steps in the workings of CLI:

1. Launching the CLI: You can open the terminal or command prompt on the operating system in use. The terminal is an application that provides access to the CLI on Unix, Linux, or macOS systems, while the command prompt is a similar application found only in Windows operating systems. 
2. Entering Commands: In the CLI, users input text commands to specify the tasks they wish to perform. For instance, on a Linux system, you can use "ls" to list files in a directory, or on a Windows system, you can use "dir" for the same purpose. 
3. Doing the Commands: Setelah perintah diketikkan, Anda bisa menekan tombol "Enter" untuk menjalankan perintah. CLI kemudian mengartikan perintah tersebut dan mencari program atau perintah terkait di sistem. 
4. Commands Execution: The CLI carries out the program associated with the entered command, performing the desired task.
5. Displaying Results: Once the program completes its execution, the CLI presents the results in a text format. These outcomes might include information requested by the user or error messages if there were any issues during command execution.

Types of CLI Commands

After knowing “what is CLI” and how it works, it’s important to learn the types of commands it offers. Command Line Interface commands can be categorized into three groups:

1. System Commands

What is CLI with system commands? These commands are used to interact with the operating system or manage various aspects of the system. Here are some examples:

1. 'cd': Change directory
2. 'dir' (Windows) or 'ls' (Linux/Mac): List files and directories
3. 'mkdir': Create a new directory
4. 'rmdir': Remove a directory
5. 'del' (Windows) or 'rm' (Linux/Mac): Delete a file
6. 'copy' (Windows) or 'cp' (Linux/Mac): Copy files or directories
7. 'move' (Windows) or 'mv' (Linux/Mac): Move or rename files and directories

2. Program Execution

Besides system commands, do you know what CLI is with program execution commands? Typically, these commands are used to run programs or applications via the CLI.

Through these commands, a program identified by the system will be executed with additional arguments or options. Examples of commonly used program execution commands include: 

1. 'node': Run JavaScript scripts or Node.js-based applications
2. 'python': Execute Python scripts or programs
3. 'java': Run Java applications or scripts
4. 'gcc' or 'g++': Compile and run programs written in C or C++

3. Batch Programs

Now, let’s uncover the concept of command line interface in correlation to batch program command. 

If you want to execute commands or scripts in batch format or script files, you should use these commands.

Batch scripts are a collection of commands executed sequentially without user intervention. For instance:

1. ‘bash’ (Linux/Mac) or ‘cmd’ (Windows): Run batch scripts in bash or command prompt 
2. ‘sh’: Execute shell scripts on Linux/Mac
3. ‘powershell’: Run batch scripts in Windows

Benefits of CLI

After discussing CLI, how it works, and its commands, it's important to understand the benefits of using the Command Line Interface. 

This user interface offers various advantages that can aid in system management and the completion of specific tasks. Here are some of its benefits:

1. Speed

CLI enables users to perform tasks quickly through text-based command lines. By directly executing commands with just a few keystrokes, the workflow process is accelerated. 

2. Resource Efficiency

Compared to graphical user interfaces, CLI requires fewer system resources. 

Graphical user interfaces demand visual elements and complex interactions, which can consume a significant portion of computer resources.

By using CLI, you can help reduce the system's resource load and achieve better performance.

3. Handling Repetitive Tasks

CLI excels at handling repetitive or frequent tasks. With this advantage, you can create scripts or batch files containing a series of commands to execute tasks automatically and consistently.

4. Power Efficiency

Since CLI does not rely on visual or graphical elements, it is more power-efficient. This contributes to reduced power consumption and maximized efficiency within the system.