Login to stargate

1. Choose a terminal app for your laptop. There are many options but here are a few:
   • Windows: Windows Terminal, PuTTY, Windows Subsystem for Linux (which is what I use)
   • macOS: Apple’s built-in terminal.app, iTerm2 (which is what I use)
2. Use your terminal app to ssh to stargate

    $ ssh username@stargate.cs.usfca.edu
   

   replacing username with your USF login ID. The password is your USF CWID. You should see:

    The authenticity of host 'remote-host' can't be established...
    Are you sure you want to continue connecting? (yes/no) yes
    username@stargate $
   

   Type ^D (CTRL-d) to exit the ssh session.

Create an ssh key pair (if you don’t already have one)

1. Create an ssh key pair using this command in your terminal

    me@mylaptop:~ $ ssh-keygen -t ed25519 -C "your_email@example.com"
   

2. You will be asked to provide a passphrase which is used to encrypt your private key. Do not forget this passphrase.

3.  me@mylaptop:~ $ cd ~/.ssh
    me@mylaptop:~/.ssh $ ls
    id_ed25519
    id_ed25519.pub
   

   • These are just text files and you can cat them to see their contents
   • id_ed25519 is your private key. You should never upload that file to any servers, or give it to anyone.
   • id_ed25519.pub is your public key. This file can be uploaded to stargate and Github.com
4. Configure stargate so your private key can be used to authenticate you on github.com

    username@stargate:~/.ssh $ cat >config
    Host *
      ForwardAgent yes
    ^D
   

Set up Github with your public key

1. Copy your public key to your laptop’s clipboard:
   • Windows Terminal: $ type id_ed25519.pub | clip
   • WSL: $ cat id_ed25519.pub | xclip
   • macOS: $ cat id_ed25519.pub | pbcopy
2. Create an account on github.com if you don’t already have one.
3. When logged into github.com go to Profile > Settings > SSH and GPG Keys and paste the contents of your public key
4. Test your ssh access to github.com from your terminal app

    me@mylaptop:~ $ ssh git@github.com
    Hi username! You've successfully authenticated, but GitHub does not provide shell access.
    Connection to github.com closed.
   

Set up ~/.ssh/config on your laptop

1. From your terminal app (you can use any editor, not just nano)

    me@mylaptop:~ $ cd .ssh
    me@mylaptop:~ $ nano config
   

   make your config file look like the snippet below. Notes:

   1. UseKeychain is macOS-only so Windows users can omit it
   2. Remember to replace your_usf_login with your USF login (e.g. phpeterson)

       Host github.com
         HostName github.com
         AddKeysToAgent yes
         UseKeychain yes
         IdentityFile ~/.ssh/id_ed25519
       Host stargate.cs.usfca.edu
         ForwardAgent yes
         User your_usf_login
         AddKeysToAgent yes
         IdentityFile ~/.ssh/id_ed25519
      

Copy your public key to stargate

1. From your terminal app

    me@mylaptop:~/.ssh $ ssh-copy-id username@stargate.cs.usfca.edu
   

2. Test your ssh access to stargate

    me@mylaptop:~/.ssh $ ssh username@stargate.cs.usfca.edu
    ...
    username@stargate:~ $
   

3. Set up ssh forwarding from stargate to your laptop

    username@stargate:~ $ cd ~/.ssh
    username@stargate:~/.ssh $ cat >config
    Host *
      ForwardAgent yes
    ^D
   

Choose one of the lab systems to work on

1. Do not do class work on the stargate host. SSH to one of the lab hosts listed by rusers

    username@stargate:~ $ rusers
    ...
    username@stargate:~ $ ssh vlab01
    username@vlab01:~ $ 
   

Finally, some code

1. Clone the assignment repository (“repo”) into your home directory

    username@vlab01:~ $ git clone git@github.com:/cs221-s22/lab01-yourgithubid
    username@vlab01:~ cd lab01-yourgithubid
   

2. Compile the program

    username@vlab01:lab01-yourgithubid $ gcc -o hello hello.c
   

3. Run the program

    username@vlab01:lab01-yourgithubid $ ./hello
    hello world
   

4. Edit hello.c and change "hello world\n" to "hello cs221\n" in lower case exactly as shown
5. Save the file and recompile it
6. Commit your changes to the local repo on the lab machine

    username@vlab01:lab01-yourgithubid $ git commit -m"change world to cs221" hello.c
   

7. Push your changes from the local repo to the remote repo on github.com

    username@vlab01:lab01-yourgithubid $ git push
   

8. ^D to log out of the lab host, and again to log out of stargate