View the video explainer for this lab on youtube

Lab 0: Git Familiarization #

The goal of this lab is to get you more comfortable with using git. You’ll need this lab in order to submit your assignments this semester, which will always be done via git.

Part 0: Creating a github account and installing software #

You are required to have a github account for this class.

If you do not have a github account #

You need to sign up for one :-) Not just for this class, but git is an industry standard used by just about any team that is writing code. Decide if you’d like to keep this git account for your entire career (don’t worry, you can make your repos private!) or use one just for this class.

1. Go to https://github.com/ and enter your info to “Sign up for GitHub”.
2. Select a username and password – your username is your github id
   • For your github id, choose something tasteful. Your name with a hyphen, like firstname-lastname could be a good choice, but choose something you like and represents you. However, remember that your github username is publicly-visible.
   • Note that for job interviews, you may want to advertise your github id, so don’t choose something like youallsuxor …
3. Use an email address you have access to and check frequently. When there are issues/updates to your submissions, you’ll get an email. You may want to use your GW email address for this. You can change your email in the future when you graduate.

If you do have a github account #

Please go to your account and check that …

You are using an email address that you check often because you will get important notifications.

Install Git on your system #

You may already have git command installed on your system. But if not, you need to do so now. Here’s how you do it in various contexts:

Mac #

On Mac, you will need to install the command line tools. To see if the command line tools are installed, Open a terminal a try to use git by simply type

git

If it is installed, you’ll see a usage info appear. If it is not installed, you will be prompted to install the command line tools. Do so. It will take about 5-10 minutes, but then you’ll have all sorts of good stuff installed, including git.

Windows #

On windows, you can install git from this link, but perhaps a better option for you is to install the Windows Subsystem Linux (WSL), which provies a full ubuntu/linux subsystem, as if it is a virtual machine.

This is a great guide from Microsoft. Once you do so, open a WSL terminal and follow the linux guide above.

Linux/Ubuntu #

If you are running a linux/ubuntu system, you can simply type

sudo apt install git

For other linux distros, refer to your package manager, but the command will be similar for yum or rpm.

At this point you should also install some other packages that you may want for the class

sudo apt-get install gcc make manpages default-jdk valgrind libreadline-dev

Extras for git #

Setup an ssh-key for your github account. This is a huge time saver and much more secure than using a password. Check out this guide.

You can also generate an access token, which you could (should!) use in place of a password when using git’s https access. Check out this guide.

Part 1: Creating your first git repo and sharing it with the course staff #

In order to submit code this semester, you will need to create a repository for each assignment, place your code in there, and upload it. You’ll also need to give access to the grading staff. These items will be a part of every project’s grading rubric. Let’s try it out together for this assignment.

Notify us with your github username #

Please find the thread on Ed titled git usernames and make a post there, so the grader knows what your git account will be this semester.

Creating a new git repo #

There are many ways to do this, but we’ll compromise between the github website and the command line. First, in your browser, log in to github.com with your account, click on the icon in the top right, select Your Repositories, and then press the green New button in the top right to create a new repo.

Under Repository name, type gitusername-lab0 but replace gitusername with your actual git username. Make sure you type it exactly as it is listed here, i.e. -lab0 must appear after your username.

Next, select the toggle button below to be Private.

Next, press the green Create repository button.

The page will load the homepage of your repo. Under the Settings tab at the top, click on Collaborators on the left hand menu, click the green Add people button, and add the following collaborators (our GTA this semester) to allow them to view your repo:
CS2113Kinga

This will send an invite (that experies in seven days) to your grader(s). They’ll be monitoring their inboxes for these items during lab; you must create this repo in your lab session to ensure the grader accepts the invite. This also means you should email the graders first if you have grading questions; the professor is not automatically added to your submissions (in general).

Part 2: Checking out your repo #

Once you have your new repo set up, click back on the Code tab, and copy the URL in the bar at looks similar to https://github.com/kdobolyi/kdobolyi-lab0.git

In your terminal, navigate to a folder of your choosing, and type (replacing it with your own URL):
git clone https://github.com/kdobolyi/kdobolyi-lab0.git

This will make a local copy of the (empty) repo in your current directory in a folder called kdobolyi-lab0 (in my case – yours will be different).

Part 3: Adding code to your repo #

Next, copy and paste the following Java code into a file in your repo’s folder, and call it HelloWorld.java:

public class HelloWorld{
   public static void main(String[] args){
      System.out.println("Hello World!");
   }
}

Tagging a file to be added to your repo #

Even though HelloWorld.java is in your folder, it is not a part of your repo until you let the server know it exists, and push it to github. This is a three step process. First, we will formally flag this file to be added to the repo with:
git add HelloWorld.java

Commiting your changes #

Next, we need to tell git that we’re ready to commit to these changes. You can ask it to commit all recent changes with the following command, which also requires a human-readable message:
git commit -m "my first attempt"

The -m flag stands for the required message between quotes.

Pushing your changes #

All this is great, but it’s only flagging this on your local copy of the files; none of this is on the github server yet. To get it there, you have to push your changes with the command:
git push

If everything goes through smoothly, you can refresh the website of your repo, and you’ll see your HelloWorld.java file there. If not, find a TA to help you.

Part 4: Making a change #

Finally, we’re going to update the file we just pushed to git. Change the string printed in HelloWorld.java to include your name. Then, go through the steps above to commit and push those changes (you don’t need to add the file to the repo, because it is already there – only new files need to be added, and only once).

Make sure that when you refresh the browser, you can see your changes there.

Troubleshooting #

• Problem: I can’t login to git using the command line

  If you are prompted to input a username and password within the command line (without being redirected online), then your password shall be the ID of you personal access token. First, create a classic access token, and check off all the permissions. Do not give anyone your token, since someone could then have full access to your GitHub. The tokens can be found and generated by clicking on your github profile photo at the top right and going to “Settings > Developer Settings > Personal access tokens > Tokens (classic) > Generate new token”.

• Problem: I’m not able to add, commit, and then push on git

  add allows you to specify which files you would like to bundle, ultimately to create a new ‘version’ of your codebase. commit takes all of the bundled files and officially defines your new ‘version’, but only locally. push takes all of your new versions and pushes them online. You may need to manually add file before committing and pushing. git status will allow you to see what files you have added and/or committed to your repo so far; it’s very useful for debugging.

• Problem: git isn’t finding my repo

  Make sure you change directory (using cd) to be inside the folder you created/cloned.

Grading Rubric #

Reminder: Worksheet J0 #

Now that you have git installed on your laptop, remember to create the repo for the worksheet from Monday’s lecture, and submit it!