===== GitHub Setup =====
=== 1. Create a SSH Key-Pair ===

Open a terminal and start the interactive generation of a new SSH key-pair.
Set your name (one single string without blanks) instead of ''alice'' in the following:

<code bash>
NAME=alice
ssh-keygen -f /tmp/id_$NAME
</code>

The program ''ssh-keygen'' will ask for a passphrase twice.
Type a passphrase of your choice and remember it: you will have to type it
quite often during the school. <color red>IMPORTANT: </color>Do not leave
the passphrase empty! If the generation is successful,
you will see something like this:

<code bash>
ssh-keygen -f /tmp/id_alice
Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /tmp/id_alice
Your public key has been saved in /tmp/id_alice.pub
The key fingerprint is:
SHA256:RJz6ek6B7z4QbUAYT0E1lbdVftsrA1khs/KUEUGxu5A student@aspp
The key’s randomart image is:
+---[RSA 3072]----+
|    .==++ooX+. ..|
|    .o..o.. O o. |
|      .+.. * +  o|
|      ooo = =   +|
|      .+SE =   ..|
|      ..... o   .|
|       oo  . o . |
|      .oo     o  |
|       ++.       |
+----[SHA256]-----+
</code>

This will have generated two files, one for the private key ''/tmp/id_alice'' and one for the public key ''/tmp/id_alice.pub''.

=== 2. Save the Public Key into the System’s clipboard ===
While still in the terminal, let save the public key into the system's
clipboard so that we can re-use it later on GitHub. Type the following, of course using your own name and do not forget the ''.pub'' extension:

<code bash>
xclip -selection c /tmp/id_$NAME.pub
</code>

The contents of that file are now in the clipboard.

=== 3. Upload the Public Key to your GitHub account ===
  * Now you want to make your public key known to GitHub, so it can be used during the school for easy authentication on GitHub. Login to GitHub: https://github.com/login

  * After login, click on your avatar on the top right of the page and in the resulting menu select ''Settings'':
  {{screenshots:ss1.png}}

  * This will bring you to the profile settings page on https://github.com/settings/profile . Here from the navigation sidebar on the left select ''SSH and GPG keys'':

{{screenshots:ss2.png}}

  * This will bring you to https://github.com/settings/keys . Here press the green button on the right labeled ''New SSH key'':

{{screenshots:ss3.png}}

  * This will bring you to https://github.com/settings/ssh/new . Here set the title to ''ASPP''. Leave the ''Key type'' to the default ''Authentication key''. Paste the public key you have saved in the system's clipboard into the ''Key'' field on this page by pressing ''Ctrl-V'':

{{screenshots:ss4.png}}

  * When you are done, press the ''Add SSH Key'' green button right below.
    You can now verify that your key has been added on the same page https://github.com/settings/keys :

{{screenshots:ss5.png}}


=== 4. Store the SSH Key-Pair on the USB-Stick ===
  * Insert your USB-stick
  * The USB-stick will be automatically mounted in the directory ''/run/media/student/ASPPXX'', where ''XX'' is the number of your stick
  * With the following command you will move the SSH-keys to the USB-stick:

<code bash> 
NUMBER=XX
mv /tmp/id_$NAME* /run/media/student/ASPP$NUMBER/
</code>


<!--=== 5. ASPP Organization on GitHub ===
If you still haven't done so, accept the invitation to join the ASPP organization on GitHub. You can do that by:

  * Log in to GitHub again https://github.com/login  
  * Go to the ASPP page: https://github.com/ASPP
  * You should see a button to accept the invitation right on top of that page
-->

=== 5. Verify GitHub Authentication  with SSH-key ===
  * Eject the USB-stick from the file manager and insert it again: a pop-up will ask you for the passphrase to unlock the private SSH key you just created
  * Open a terminal and try the following:

<code bash>
ssh -T git@github.com
</code>

If after that you get something along these lines:

''Hi Alice! You've successfully authenticated, but GitHub does not provide shell access''

everything went well. If you instead get something like:

''git@github.com: Permission denied (publickey)''

something went wrong.