Lab 1

DSAN 6000 Fall 2025

Important

Make sure that you are connected to the Saxanet WiFi network and not the GuestNet network. SSH (TCP port 22) is blocked on GuesNet which means if you are on GuesNet you wil not be able to connect to your cloud VMs or clone repos from GitHub via SSH. Use SaxaNet. #

Overview

Goals

Creating your public/private ssh key pair and knowing where to find the files
Learning to use GitHub Codespaces IDE
Learning the Linux Shell
BASH Exercise

Terminal Setup

We will be using the Terminal in many tasks in this course. By “Terminal”, we mean a command-line terminal, where you will use it to type instructions and connect to your remote resources.

When we say “terminal” in this course, it means that you need to open up the terminal application for your respective operating system. The terminal is a “local” application, meaning it is running on your “local” machine (your laptop.)

Windows Users

Windows users will be using the Windows Powershell: <https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/powershell>

Windows Powershell is most likely installed if you have Windows 10. If you don’t have Powershell, take a look at this article: https://www.howtogeek.com/336775/how-to-enable-and-use-windows-10s-built-in-ssh-commands/ that explains how to install it.

You can find Powershell by typing “Powershell” into the search bar:

Once Powershell is running, this is your terminal:

Additional Powershell Configuration (you must do this!)

You need to perform this step **only once** to be able to use agent forwarding which is explained further in the lab.

Exit Powershell if running
Start a new Powershell session using run as Administrator
Enter the following command (you can cut/paste from here):

Get-Service -Name ssh-agent | Set-Service -StartupType Manual

Exit Powershell. You should not need to run as administrator going forward.

Mac and Linux Users

For Mac and Linux users, you will open up the Terminal.

Macs and Linux have a built in Terminal.
Or, you can use iTerm app: <https://www.iterm2.com/>

If you are on Linux (but not on Mac), you can open the terminal by using Ctrl-Alt-T.

SSH Keypair Setup

When you want to connect to a remote machine, the method is called “Secure Shell”. This creates a connection between the local machine (where your terminal window lives) and the “remote” machine (where the commands you will send actually execute). In order for the local and remote machines to authenticate (trust) each other, we have to create a special password-like files called a keypair. It is called a keypair because there is a public version and a private version. Read more about SSH Keys here.

NOTE: You only need to create your ssh public/private keypair one time only. If you already have a public/private keypair on your laptop let us know.

Open a terminal (on your laptop) if not already open. By default, every time you open a terminal it will open in your home directory.
At the command prompt run the following command: ssh-keygen -t rsa -b 2048 and press enter
You will see this prompt, just press enter

Generating public/private rsa key pair.
Enter file in which to save the key (/home/User/.ssh/id_rsa):

You will see this prompt, just press enter

Created directory '/home/User/.ssh'.
Enter passphrase (empty for no passphrase):

You will see this prompt, just press enter

Enter same passphrase again:

You will see these messages (your randomart will look different) and your keypair has been created.

Your identification has been saved in /home/User_name/.ssh/id_rsa.
Your public key has been saved in /home/User_name/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:xPJtMLmJSO73x/NQo3qMpqF6r6St4ONmshS8QZqfmHA User_name@WinDev1802Eval

The key's randomart image is:
+---[RSA 2048]----+
|                 |
|       . .       |
| .  . . *        |
|+. o . = *       |
|++E o . S o o    |
|.=+o     . o .   |
|+oo o o  +o      |
|+= +.o oo.*.     |
|*+=++ooooo o.    |
+----[SHA256]-----+

See your key files

Open a terminal if not already open
Change to your .ssh directory
- This is a hidden directory so if you list your files using ls you won’t see it. For seeing all files, use ls -la.
- To change into the .ssh directory type cd .ssh

Type pwd to print your current working directory.

Windows users in Powershell will see:

PS C:\\Users\\your_name\.ssh> pwd

Path
----
C:\\Users\\your_name\.ssh


PS C:\\Users\\your_name\.ssh>

Mac users will see:

pwd
/Users/myusername/.ssh

Linux users will see:

\$ pwd

/home/myusername/.ssh

Next, we need to open the new key file we just made.

Type ls to list the files in the directory.
- What is displayed may look different. You will not have a config file unless you have already created one.
Type ls -la to list all the files in the directory, even the hidden ones.
- What is displayed may look different. You will not have a config file unless you have already created one.

Get your public key info

The file id_rsa is your private key and this file will not leave your computer.
The file id_rsa.pub is the public key, whose contents we will upload to cloud services so you authenticate.
The known_hosts is a file that gets generated as you connect to different remote systems.
- This is useful so you know you are connecting to the same server as previous times.

\$ ls -la

total 32

drwxr-xr-x  6  your_name staff   192 May 29 20:39 .
drwxr-xr-x+ 75 your_name staff  2400 May 30 13:35 ..
-rw-r--r--  1  your_name staff   181 May 29 15:50 config
-r--------  1  your_name staff  3243 May 29 15:50 id_rsa
-rw-r--r--  1  your_name staff   742 May 29 15:50 id_rsa.pub
-rw-r--r--  1  your_name staff   363 May 29 20:42 known_hosts

View the contents of your public_key file by running the command cat id_rsa.pub
- What is shown is a sample public key, yours will be different

\$ cat id_rsa.pub

ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCnKuIRXwZu0JZH0/Q2XNrYYTaJT7bMtXGhGQaSSOZs6MhQ4SkSbHiygO7RauQf741buLnASzY27GKMMMml6InwfxJWrF60KhNK0r869POQkuZa9v9/cmYcEIzmAJe1xRPABEZ2yfbTG9Wq4sg9cU0mwt1Bx7wiN4QNf0Bak62EC8JWTbcKLduuzO1zabIb5xW9gfR9b4K3HwmqRLl18S8bNsfYQZfvtlwd0mCWQUeuEGbDOgqh//nLIj6DeXdyxbD5xrz79iOAuAK2nXAjNCEtKpxNGQr2Py7aWQjlH+U5laDEHVg4hzmBY7yoZ5eC3Ye45yPqpQA1y8JrbXVhPJRP User\@WinDev1802Eval

Extracting your public key

Open a text editor (Notepad on Windows or Textpad on Mac, NOT MICROSOFT WORD) and select the output of your terminal with all the text from the ssh-rsa beginning all the way to the end, and paste it in your text editor as-is. We will use this in the next step.
- You can also just copy/paste from your terminal screen.
- On a Mac, you can also copy the contents of the id_rsa.pub file using

pbcopy < id_rsa.pub

GitHub Setup

Adding SSH Key to GitHub

a) Create a GitHub Account if you do not already have one

Go to www.github.com to create a GitHub account if you do not already have one. Your username has to be globally unique, and the email address you use to register GitHub can be any email address you own.

b) Upload your Public key to GitHub

Log into to your GitHub account if you are not already logged in
Click on your profile icon on the top-right of the screen and select Settings from the dropdown
Click on SSH and GPG keys from the left hand menu
Click on the New SSH key button on the top-right
Give your key a name. This is just a name and is meaningful to you.
Paste the contents of the public key in the Key box. Leave the “Key Type” dropdown as “Authentication Key”.
Click the Add SSH Key button

c) Test that your ssh key works with GitHub

Open a terminal if not already open on your laptop
At the command prompt, type ssh -T git@github.com and press enter to test. If it works, you will see something like this, with your GitHub username:

The authenticity of host 'github.com (192.30.253.112)' can't be established.
RSA key fingerprint is SHA256:nThbg6kXUpJWGl7E1IGOCspRomTxdCARLviKw6E5SY8.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'github.com,192.30.253.112' (RSA) to the list of known hosts.
Hi wahalulu! You've successfully authenticated, but GitHub does not provide shell access.

You are now ready to use ssh authentication with GitHub.

Create a Personal Access Token on GitHub

Log into to your GitHub account if you are not already logged in
Click on your profile icon on the top-right of the screen and select Settings from the dropdown
Click Developer settings
Click the Personal access tokens tab
Click the Generate new token button
Enter a token description (you can call it big-data-class)
Select the repo permission, and then click the Generate token button

Copy the token and save it in a text file. You will need this token later on in the semester and if you lose it you will need to re-generate a token

GitHub Codespaces IDE

Codespaces is an integrated developer environment (IDE), which provides you with a VS Code environment with a cloud computing backend. The repository is automatically loaded into your environment and you do not need any additional authentication steps to push to your repo. Read more here about Codespaces.

In this lab, we use Codespaces to get you familiar with the Linux terminal.

You will not use Codespaces for most of your work this semester. If you were just exploring code or making minor changes to a project, Codespaces could be a simple solution.

Launching Codespaces

Open your Git repo for the lab. Launch Codespaces from your repo by clicking on the green code button, then select “codespaces” then click “Create codespace on main”.

Wait for the workspace to be created. It will set up the computing instance with a screen like this.

Linux Terminal in Codespaces

You now have full VS Code capabilities. The terminal in Cloud9 is the lower window. You are connected to a cloud computing instance and are able to run BASH commands (along with other programming languages) there.

Check out the cheat sheet on Linux commands here.

BASH Walkthrough

The instructor will walk through slides and code live to demonstrate basic Linux commands.

BASH Exercise

GitHub Classroom Link

Go to Codespaces and complete the BASH Exercise that is located in the Readme.