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C'est la Z

SIGCSE 2017 - a path to github part 1

Both at and prior to SIGCSE 2017, I promised to write up the steps I take to introduce and use revision control systems in my classes.

This series is not meant to be a git or GitHub tutorial. There are plenty of those already (two of which I've linked to below). This is about the process I use with my students to get them up to speed.

As with any new tool, there will be some resistance but once git saves them once, they get religion. There will also be some bumps in the road but at the end of the day, the students will be using a valuable and necessary tool.

I was also surprised at the ancillary benefits I got as a teacher by using GitHub in particular. I'll talk about that at the end of the series.

Here's part one.

I'm doing this with git and GitHub but there's no reason why other systems and hosts can't be used. I'd also recommend that any educator or student sign up for the assorted discounts offered by GitHub.

I've followed this basic idea multiple times and done it over the course of a single semester, a year, and even two years. Regardless of time frame, the idea is the same. Make each step simple and relevant and introduce complexity and roadblocks a piece at a time.

Step 1 - code distribution

To start, I don't even talk about version control. We start with code distribution. For years, I've looked for efficient ways of sharing code with my classes. Both code developed in class and code for assignments.

I've tried things like NFS, Dropbox, online code repositories like the files section of systems like Moodle or Blackboard.

At Stuy, we've always had efficiency problems with NFS and Dropbox has multiple problems ranging from students not being able to install the client on school machines to the problems of the network hit when a room full of kids are syncing at the same time.

Uploading to a CMS system was also problematic - I'm a command line wonk and hate going through slow web page menus to navigate a filesystem and upload files. I also had to remember to get the files off of whatever machine I was working on in class and then transfer them to the CMS when I had a free moment.

Enter git. Now, of course, if you're going to use git in the classroom you have to know it. There are plenty of resources out there. Online courses, articles, videos, and tutorials. Here are a couple:

I also want to point out that I just use raw command line git along with native GitHub. GitHub has rolled out GitHub Classroom which adds a layer of support for educators. I don't use it because, as I said, I'm an old school command line wonk and also because I figured out a sequence that worked for me and my students before GitHub Classroom existed. Were I starting now, I'd take some time to look at their current offerings before jumping in.

Set up

Before starting, make sure you register your ssh keys. This help page has more information. You'll want to register an ssh key from every machine you use - home, work, laptop.

Now go over to GitHub and make a new repository. I usually name it classcode. BEGINNER NOTE: when creating the repo, make sure to check the "initialize this repository with a README" box. If you don't you'll be given a set of instructions on how to set things up once you click Create repository but it's easier and easier to follow if you start with an initialized repo with a README.

I make the repo public – it's code I'm distributing – nothing to hide here. If you aren't comfortable with that, just make the repo private. If you've registered as a teacher with GitHub, you can set up an organization and you'll be able to set up free private repos within it. The other downside here is that you'll have to individually give each student access to the repo. That's a mild annoyance but it only has to be done once.

Teacher use

Next, clone out the repo. BEGINNER NOTE: Make sure you check out the ssh version not the https version. Just make sure that when you click the clone button, it says "Clone with SSH." If not, just click the "Use SSH" link in the same box. Students will clone the using https.

From the teacher point of view, you can just start using the repo. My work flow is typically:

  1. git pull at the start of class
  2. write code throughout class
  3. git add, git commit, and git push at the end of class

I use a similar flow when I want to add files in my office or at home.

Student use

From the student point of view, assuming a public repo, they just have to clone the repo and at the beginning of every class or work session, do a git pull. That's all there is to it.


That's it. The kids are now using GitHub – they're probably looking at and poking around on the web site as well as pulling files to their machines. You can also, in class, show things like git status, git log, and git diff to set the stage for step 2 of this process and beyond.

Since the students aren't adding, committing or pushing, you probably won't get any errors.

The only problem that could reasonably occur is if a student places a file in their local copy of the repo with the same name as something they haven't pulled yet. This is pretty easy to address and provides a nice stepping stone lesson to again, set the stage for more complex operations.

I'm happy with this as a first step towards git using GitHub. It provides a nice way of sharing class code while gently introducing the students to the tool.

The next step is having the students add files to a repo. That's the next post in this series.

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