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Not knowing how to use a terminal would be like a writer not knowing how to use a computer; sure they could use a typewriter or good-old pen and paper, but how effective would they be?
The terminal is a program that you use to type in commands. It is a text input/output environment. In this article, we'll cover what a terminal is, introduce you to a couple of useful commands, and talk briefly about what commands are.
The default terminal is usually white, but you've probably seen black terminals in movies. Featuring a geeky hoodied-hacker doing something like "running an algorithm" or "extinguishing the override" or some other nerd'ish lingo nonsense. Take, for example, the terminal making an appearance in these well-known movies:
From left to right, these images are from Girl With The Dragon Tattoo, The Fifth Estate, Snowden, and The Matrix.
Let's start things off by opening your terminal; every major computer comes packaged with a terminal program.
1. macOS Users: There are several ways to open the Terminal on a Mac. I will use Spotlight. To use Spotlight, press cmd + spacebar. Then type in "terminal". You should see the Terminal application come up. Click on it.
I>When talking about the actual Terminal application that comes packaged with macOS I'll capitalize the "T." Otherwise, terminal with a lowercase "t" will refer to any terminal program that interfaces with your Shell. Thus, I can use the lower case terminal to generically talk about both the macOS Terminal application and the Windows OS Powershell.
1. Windows OS Users: The dominant Shell-CLI environment for Windows 10 users is PowerShell. To navigate to PowerShell, search for the "PowerShell" in the File Explorer and open it up.
Before we start typing commands into the terminal, let's chat briefly about what commands are.
As we'll learn more about in tomorrow's article, the terminal works with the Shell of your computer. If you remember from Day 3, the Shell wraps around your computer's Operating System, or more specifically, your Operating System's kernel.
Shells take commands, process them, and then do something in response. For example, when you make a folder on your computer, you are using a program that, like the terminal, commanded your computer's Shell to make a folder. The Shell communicated with the computer's kernel to do as you asked.
The terminal is similar, but instead of clicking on menus to make a folder, you type those commands. For example, making a folder can be done using the following command inside the terminal:
mkdir
mkdir stands for "Make Directory."
Here's what it looks like using the macOS Terminal application to "Make a Directory" called newFolder on my Desktop.
T> When you run the terminal, you are issuing commands directly to the Shell. You may see a $ when you open the terminal program. The $ is Shell's symbol for indicating that it's ready to take a command.
Now, if I look at my Desktop using my Finder program, I'll see the folder called "newFolder."
I>Folder and Directory essentially mean the same thing. "Directory" is a classical term used when Shells and terminal programs were being developed. "Folder" is a more visual word that came about as Finder and File Explorer programs came into existence. Technically, a Directory maps to a file system, whereas Folder is a less specific term. Because the Shell programs are older, they tend to always use Directory instead of Folder, e.g., mkdir make directory.
1. Download the shell-script-practice.sh file to your downloads folder on your computer.
2. If you'd like to peak, go ahead and open this file with your text editor. The code you see is written in the Bash Scripting language; a programming language that works with the Bash Shell. The Bash Shell is the default Shell that comes with macOS.
W> Windows Users, I am going to stop ✋ you and ask you to download the Bash Shell. You will need to do this before proceeding to the rest of the exercise. My preference would be not to have you download any additional software. However, the reality is Bash is so common that you'll eventually need it. Here are the instructions. Installing Bash on Windows is now common, so if you run into any issues, hit up Google.
3. Next, open your terminal as we practiced earlier.
4. From your terminal, we are going to issue our first command called pwd, short for "Print Working Directory." This command tells us in our computer where we are. The concepts of "where" will be more thoroughly addressed when we talk about File Paths in Day 25 and 26.
In your terminal type the following:
pwd
The terminal should return something like the following.
The "Print Working Directory" command returned where I am on my computer's file system. In this example, I'm located on the Users "angel" directory. If I were on my Desktop, it would return something like /Users/angel/desktop.
5. Next, we're going to tell the terminal to move us into our computer's Downloads folder. To do this, we are going to use a command cd, short for "Change Directories."
Type the following command in your terminal:
cd ~/Downloads
You can see the "Change Directories" command used in the following screenshot. I also followed that command with another pwd to confirm that yes, I am now in the Downloads Folder.
Now that we're in our Downloads folder, we can run the "shell-script-practice.sh" file we downloaded in Step #1.
To run the "shell-script-practice.sh" file, run the following command:
bash shell-script-practice.sh
The script will then ask you a couple of questions, go ahead and answer them.
Let's recap what we just did.
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We used the terminal to navigate to our computer's Downloads folder.
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We then told the terminal to use the Bash Shell to open the file "shell-script-practice.sh". If you peeked at the code in this file, you would have seen Bash Scripting language that walks you through those questions.
Nice work 👏. You just got your first taste of using the terminal and running a Shell script. If this all seems like a lot, that's OK. It is. This article is just an introduction. Learning about Shell Scripting, and most importantly, how to use the terminal will be crucial as you learn more about Web Development.
Tomorrow we'll be talking about CLIs (pronounced "C L I") and GUIs (pronounced "Gooey"), and their relationship with the terminal program and your computer's Shell.