Revision Control with Git


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Using Gitlab

For this quarter, starter code for each of the programming assignments should be hosted on a git repository on UCSD’s git server: This is where each of the programming assignments will be retrieved from. In addition, you will be required to develop your assignments using git and this will also act as your turnin. When you finish your assignment, your work will be downloaded from your Gitlab repository and graded. Therefore, you should allocate some time to familiarize yourself with git and Gitlab well before the assignment due date.

The following instructions have references to "pa1" for programming assignment 1. Replace all instances of "pa1" to "pa2", "pa3" etc. based on the programming assignment you are working on.

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Git Tutorials

Git is a distributed version control system that is used when developing software in industry and is a very powerful tool. If you are not familiar with git, you can check-out a quick tutorial here:

This is in addition to the assigned reading for Git in class.

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Preparing your Git Environment

The following steps are intended to be performed in the labs. However, you can also do this via SSH if you are familiar with accessing the school servers via this protocol. This tutorial will not walk you through installing and using an SSH client.

For git to work correctly, a proper .gitconfig file will need to be defined. This file stores your information such as name, email, and other git related specifics. We will be focusing on a small subset of configuration details to get you up and running quickly.

To start, you should sign into one of the lab machines running linux (NOT WINDOWS) and launch the terminal application. We will not be holding your hand on how to open the terminal emulator. You are CS majors and should be able to figure this out. :)

The file we are about to configure can be found in your home directory ~/.gitconfig after we have completed the steps below. You should make a backup of this file as it can be used on any machine where you will be using git—even for future classes. Git comes with a tool called git-config that lets you get and set configuration variables that control all aspects of how Git looks and operates. You will be using this tool to define some global configuration settings. By defining these settings globally, they will apply to all your git projects for this class as well as other classes.

At the command prompt issue the following commands:

git config --global "John Doe"
git config --global
git config --global core.editor gvim
git config --global merge.tool gvimdiff

Yes you should replace John Doe as well as his email with your name and email -- and please don’t email John Doe.

Once you have entered the commands above, you should verify that you spelled everything correctly. Actually, you should have done this before pressing enter, but just in case, you can do this via the following command:

git config --list

If you made a mistake, simply reissue the command above that you entered incorrectly with the corrections made and it will overwrite the previous setting. Tip: To avoid being stuck at this step indefinitely, at some point, you are going to want to stop making mistakes.

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Creating your Repository

In order to start your assignment, you MUST create a repository in the cse100-sp15 group. The easiest way to do so is to create your repository following the instructions below: If you are working with a partner, ONLY ONE OF YOU should perform this step.

  1. Go to Click the green New Project button. (If you cannot access the group, or if the New Project button is not available, it is probably because the staff has not yet added you to cse100-sp15. In this case, please send an email to one of the TA’s so they can add you to the group)
  2. The project name should include your username and the number for this programming assignment. For example, if your name is Zack and your username is zgrannan, then you should name the repository: PA1-zgrannan. If you are working with a partner, and his name is Gautam and his username is gakiwate, you should name the repository: PA1-zgrannan-gakiwate. You could also name the repository PA1-gakiwate-zgrannan.

    Make sure that the names are your username and not your actual names. Your repository name should not contain any spaces!
  3. Click the "Import Existing Repository" link, which is directly below the namespace drop-down list, and paste the starter-code repository location exactly as it appears:

    Make sure it starts with https:// and ends in .git
  4. Ensure the namespace is cse100-sp15. If the repository is not in this namespace, your code will not be accessible by the professor.
  5. Description is optional
  6. Make sure the visibility level is Private. This is very important, because otherwise your code will be visible to everyone.

    At this point, your screen should look something like this:

    Double-check that the project name contains the text pa1 followed by your username, the namespace is cse100-sp15, you are importing the correct repository, and that the visibility level is set to Private.
  7. Finally, click the Create Project button.
  8. It should take less than a minute for your repository to be created.

  9. Next setup your ssh key with gitlab on the machine that you plan to clone your repo. This may be your laptop or one of ieng6's dedicated servers. If you plan to work on the servers, first ssh into the server using your cs100s or ACMS account. Then setup your ssh key with gitlab.

    If you don't know how to create an SSH key, look here:

    1. ssh-keygen -t rsa -C ""
    2. Generating public/private rsa key pair.
      Enter file in which to save the key (/home/linux/ieng6/oce/1h/your_username/.ssh/id_rsa): [Press Enter]
    3. Enter passphrase (empty for no passphrase): [Type a passphrase]
      Enter same passphrase again: [Type passphrase again]
    4. Your identification has been saved in /home/linux/ieng6/oce/1h/your_username/.ssh/id_rsa.
      Your public key has been saved in /home/linux/ieng6/oce/1h/your_username/.ssh/
      The key fingerprint is:
    5. cat ~/.ssh/
    6. Copy and paste the key to your profile at:

  10. Now you are all set to clone your repo over SSH. To do this type in the following command:
    git clone

    Replace pa1-gakiwate with YOUR repository name. Also note that this is case-sensitive, so your repository name should be in all lower-case letters.

    You should have a clone of your repo on the machine that you plan to develop your code.
  11. Sometimes updates will be made to the starter code after you have already cloned the repository. To retrieve these updates run the following command INSIDE the directory you just cloned.

    git remote add starter

    When updates are announced, get the updates with the following command:

    git pull starter master.
  12. To test that you have the correct permissions on the repository, you may make a modification to README, then run:

    git add README
    git commit -m "Test Modification"
    git push origin master

If you are working with a partner, go to:[your repo name]/team and click new project member. From there you can add your partner to the repository. Once added, they should be able to clone the repository on their own machine.

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Working on your Code

At this point, ensure that both you and your partner can access your newly created repository. Whenever you push to the repository, you should be able to view your changes online at:[your repo name].

At any time, you can view the version of the code that the instructor will download at:[your repo name]/repository/archive.tar.gz.

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Renaming your Repository

If you need to rename your repository, please follow these instructions:

  1. First, go to the edit page for your repository at:[your current project name]/edit

    For example, if your current repository name is pa1-zack, then you would go to:
  2. In the textbox next to "Project name", please enter the correct repository name. Remember that your project name should be in the format pa1-[your ACMS username] if you are working by yourself, or format pa1-[your ACMS username]-[your partner's ACMS username] if you are working in a pair.
  3. On the bottom of the screen click the blue "Save changes" button.
  4. Now, go to the "Dangerous Settings" area at the bottom of the page, and click the "Show it to me" button. Scroll down to the "Rename Repository" section.
  5. In the "Rename repository" section, set the Path textbox with the same text that you used in the Project Name textbox. For example if the correct name for your repository is pa1-zgrannan it should look like the picture below:

  6. Click the red Rename button.
  7. If you have already cloned your repository, you must run the following command inside the cloned repository folder in order to point your local repository to the remote location:

    git remote set-url origin[your project name].git

    For example, if your new repo name is pa1-zgrannan, you would use the following command to rename your repository:

    git remote set-url origin

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Deleting Your Repository

If you need to delete your repository, simply rename it as paX-delete, following the instructions in the previous section. The tutors will delete all repositories with the keyword 'delete' for you. You don't have to wait for your repository to be deleted after you have renamed it, to start working on a new one.

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