Command Line Basics

Using Tessel is just like web development. But if you’re not familiar with web development, you might want to take a minute or two to get comfortable with some key tools of the trade: the command line (the “terminal”, where you execute commands) and the text editor, where you will work on and save your programs.

Select the operating system you are working on.

| OSX || Linux || Windows |

Open up the application on your computer called “Terminal” by pressing ⌘ + SPACE and typing “Terminal”.

Its dock icon looks like , and the terminal will look something like

You can use the terminal to write commands to your computer (this is the “command line”). Let’s try it out!

In your terminal, type

ls

and hit enter.

The ls command, short for “list”, tells your computer to list all of the file names for the folder you’re in. Your list of files probably includes “Desktop” and “Documents”, among others.

Let’s try another command: type

cd Documents

and hit enter.

You are now in the Documents folder; cd means “change directory”. If you try ls again, you should see the contents of your Documents folder listed out. If you want to compare, open up Finder and look in Documents to see the same files.

Let’s get back to the folder we were in before: cd ..

You changed directory again! ls to see what we have here. You’re back where you started! The .. after cd tells it to go up one folder in the directory.

Ok, now you’re a cool hacker who can use the terminal (or “console”) to write in the command line.

(If you want to learn more commands, there are a whole bunch of them here. I recommend pwd, open, mkdir, touch, mv, and cp.)

Open up the application on your computer called “Terminal” by tapping the SUPER key (Windows or Apple key, depending on your hardware) and typing “Terminal”.

Its icon looks like , and the terminal will look something like

You can use the terminal to write commands to your computer (this is the “command line”). Let’s try it out!

In your terminal, type

ls

and hit enter.

The ls command, short for “list”, tells your computer to list all of the file names for the folder you’re in. Your list of files probably includes “Desktop” and “Documents”, among others.

Let’s try another command: type

cd Documents

and hit enter.

You are now in the Documents folder; cd means “change directory”. If you try ls again, you should see the contents of your Documents folder listed out. If you want to compare, open up Finder and look in Documents to see the same files.

Let’s get back to the folder we were in before: cd ..

You changed directory again! ls to see what we have here. You’re back where you started! The .. after cd tells it to go up one folder in the directory.

Ok, now you’re a cool hacker who can use the terminal (or “console”) to write in the command line.

(If you want to learn more commands, there are a whole bunch of them here. I recommend pwd, open, mkdir, touch, mv, and cp.)

Open up the application on your computer called “Command Prompt”.

If you’re not on Windows 8, go to the start menu and type “Command Prompt”.

If you are on Windows 8+, swipe right to find “Windows System”, within which you can find “Command Prompt”.

Its icon looks like , and the application (the terminal) will look something like

You can use the terminal to write commands to your computer (this is the “command line”). Let’s try it out!

In your terminal, type

dir

and hit enter.

The dir command, short for “directory”, tells your computer to list all of the file names for the folder you’re in. Your list of files probably includes “Desktop” and “Documents”, among others. Let’s try another command:

Now type

cd Documents

into your command line and press enter.

You are now in the Documents folder; cd means “change directory”. If you try dir again, you should see the contents of your Documents folder listed out. If you want to compare, open up My Comuter and look in Documents to see the same files.

Let’s get back to the folder we were in before:

cd ..

You changed directory again!

dir

to see what we have here. You’re back where you started! The .. after cd tells it to go up one folder in the directory.

Now you’re a cool hacker who can use the terminal to write in the command line. (If you want to learn more commands, there are a whole bunch of them here.)

When you use a command line tool, you’re using a grammar-like structure. Items are separated by spaces, and it’s usually like this:

tool action object -flag <flag-object>

The “tool” is like a program you’re calling; the “action” is the action you want the tool to perform, and the “object” is the object you want the tool to perform the action on. “Flags” are for passing in extra objects For example, on the next page you will do:

npm install t2 -g

This means:

“use the tool called ‘npm’ to perform the ‘install’ action on the item called ‘t2’. Do this globally.” t2 is the command line tool you will use to talk to the Tessel 2. -g stands for globally– which is to say, you want npm to install such that you can use the t2 tool even outside the folder you were in when you installed it.


Text Editors

You will also need a text editor to save your JavaScript files. This means a plaintext editor, not a Word document.

We recommend that you download one of these (you can download for free):

Typically, directions that belong in the command line are one line, whereas longer scripts, such as anything in JavaScript, should be typed into the text editor and saved, then run through the command line.

In the context of this tutorial, things that should be run in the command line look

like this

And scripts that should be saved in the text editor will look

like this

You’ll see this when you get to the blinking lights example. But don’t skip ahead– you’ll need the tools we install in the next step.

Fork on Github