What is a Command Line Interface (CLI)?

• It’s text-based interface where people (mostly developers) use commands to do a task on computer.

Google bard says:

CLIs can be intimidating for people with no computer science background, but they are actually quite easy to learn. There are many resources available online, and most operating systems come with a built-in help system.

Who use it, and why do people use it?

• Mainly developers use it
• They can use it for all things they can do with a graphic interface: look for a certain document, check the directory, and install software and packages. Developers mainly use it as part of their workflow to build, debug, test and deploy software. Typical things they could do with a CLI are: build a pipeline for testing environment, install packages, run their test, and run application specific command, e.g. github deployment

The provided cheatsheet shows various commands, some closer to natural language (e.g., "open" + file name) than others (e.g., "cd~" and "ls"). Computer languages contain syntax and jargon that can still pose challenges for users. Thus, understanding and familiarizing oneself with these commands is crucial for optimal computer productivity and takes time and brain power.

Any application can have CLIs in theory, on MacOS, we have a system CLI, which you can use to open the GUI of the application. If an application supports CLI, you can install it from your terminal and also use CLI in the console to use that application.

And again according to google bard, here are four ways to use CLI more efficiently:

Use the help system. Most operating systems come with a built-in help system that can provide information about the commands that are available.

Use tab completion. Many CLIs support tab completion, which can help you to complete commands more quickly.

Use aliases. Aliases are shortcuts that you can create for commonly used commands.

Use scripts. Scripts are a way of automating tasks. You can use a script to run a series of commands with a single command.

Even though developers are pretty smart and have good memories, they still have to remember loads of commands in their heads while juggling other work. It can be a real struggle to keep everything straight!

Are there ways we could make the CLI flexible, and more powerful as a tool? Definitely, yes. By adopting some simple UX principles, CLI can be user-friendly and beautiful, too.