By Test Engineer Christian Medders

Why the CLI Matters for Developers

The command-line interface (CLI) has been an important tool for developers since the early days of computing. From the first computers that relied on punched cards and teletype machines to the modern era of powerful workstations and cloud computing, the CLI has evolved alongside technology to become an essential part of software development. In this blog post, we’ll delve into the history of the CLI, discuss the different types of shells available, and explain why it remains a crucial skill that every developer should possess.

History of the CLI

Terminals allow users to interact with computers via a keyboard and display. Since their introduction in the 1960s, they have mostly been used by programmers and system administrators to run tasks on computers. During this period, personal computers were not yet common, and their utility was limited.

In the 1970s and ‘80s, the CLI progressed alongside the advent of Unix, a versatile, multiuser, multitasking operating system. Unix introduced shell scripts, enabling users to automate tasks and workflows through a sequence of commands, thus enhancing the efficiency and power of the CLI. Although the graphical user interface (GUI) has largely replaced the CLI by allowing users to interact with computer functions through visual icons and menus, proficiency in using the CLI remains a valuable skill for developers. Mastery of the CLI empowers developers to work efficiently, automate tasks, and troubleshoot issues effectively.

Available Shells

A shell is a user interface that processes all commands entered on a CLI. It reads and interprets the commands and directs the operating system to execute tasks as requested. Essentially, a shell is a user interface that oversees the CLI and serves as a middleman, facilitating the connection between users and the operating system.

There are numerous different shells available, each with its own advantages and disadvantages. Some of the shells include:

• Bash (Bourne-Again Shell)—This is one of the most widely used shells and is the default shell on many Linux distributions.
• Zsh (Z shell)—Another popular shell, it offers many advanced features, is very customizable with Oh My Zsh, and is the current default on MacOS.
• fish (Friendly Interactive Shell)—A newer shell that aims to make CLI easier for beginners.
• Bourne Shell (sh)—The first default shell, created in 1979.

Key Benefits of Knowing the CLI

Understanding how to use the CLI is crucial for developers as it enables them to work efficiently and effectively. Here are several reasons why:

• Speed—The CLI proves to be much quicker than using a GUI for various tasks. Navigating through directories, running tests, and deploying applications can all be accomplished more efficiently using the CLI.
• Automation—Developers can automate repetitive tasks using scripts through the CLI, which helps save time and reduces errors. This facilitates tasks such as building and deploying applications, backing up data, and monitoring servers.
• Collaboration—Many development teams use the CLI for project collaboration. By sharing scripts and commands, team members can work together more seamlessly and minimize misunderstandings.

While the CLI is valuable and essential, it does have some downsides to consider:

• GUI is more user-friendly and offers a more intuitive interface.
• There is a steeper learning curve associated with memorizing commands and understanding complex syntax and arguments. However, it is possible to assign aliases and automate commands to mitigate this challenge.
• Different shells may require the use of different commands, further adding to the learning process.

To list your files and folder: 

MacOS -> ls
Windows -> dir

To see the full path of current folder/directory:

MacOS -> pwd
Windows -> cd 

Why This Matters

While the CLI may be considered old-school by some—especially with the rise of user-friendly integrated development environments (IDEs) like VSCode and others—it remains a vital tool for developers. Its flexibility, speed, and power make it an essential component of every developer's toolkit. Whether you're a seasoned professional or just starting out, mastering the CLI will enhance your productivity and effectiveness, while also unveiling new possibilities for your development skills. Proficiency with the CLI can have a large impact on end users by enabling the quick and effective delivery of products. With the CLI, developers can seamlessly transition to any project and can start building without the hurdles of having to learn a new tool or service.

Moreover, understanding and using the CLI not only expands job opportunities for developers, but also grants an advantage over those who are unfamiliar with working with terminals. As the popular saying goes, everything always comes back around.

So, if you haven't already, explore and leverage the CLI more. Create files from your terminal, navigate new directories, and embrace new command-line experiences—you won't regret it!

List of Useful Commands with Examples

• mv—Move files around. You will need to follow this command with the current path of your file followed by the intended destination.
  • Example: mv projects/helloWorld/index.html repos/helloSpace/index.html
• cat—Concatenate. Display contents of a file in terminal by adding the file name at the end.
  • Example: cat index.html
• cd—Change directory. You will need to add the file path to move to that directory.
  • Example: cd projects/helloWorld/index.html (this will take you to the index.html file in the helloWorld directory)
  • Example: cd .. (this will move up a directory)
• pwd—Print working directory. Use this to get an idea of which directory you might be in.
• history—See the previous commands you have run. You can also use the up arrow to rerun a command from your history.
• ls—List directories.
  • Example: ls –la (will list all content including hidden files)
• mkdir—Make a directory.
  • Example: mkdir helloWorld (will make a directory with that name)
• touch—Make a new file in which ever directory you are in.
  • Example: touch index.html (will add that file)
• clear—Will give you a clean terminal window.
• whatis—Will give you a brief breakdown of any command.
  • Example: whatis cd (Will give an overview of the cd command.)