Version control with Git and GitHub

1. Open the notes at http://gcapes.github.io/git-course/
2. Make sure you’ve completed all the setup steps at https://gcapes.github.io/git-course/setup.html

Research-related IT services

• Go to the Research IT website for links and info on
  • Training courses teaching computing skills for Research
  • General guidance and advice about research software
  • Specialist support and consultancy e.g. code reviews
  • HPC systems and data storage
  • How to get in touch with us
  • Newsletter and twitter for updates

Course timing

• 09:00 – 12:00 Morning session
• 12:00 – 13:00 Lunch
• 13:00 – 16:00 Afternoon session

Teaching methods

• Interactive, workshop-style course
  • Code along with the examples
  • Test your understanding in the exercises
• Course notes
  • All examples and exercises are in the notes
  • Slides will remain online after the course

Getting help

• Sticky notes/zoom reactions
  • Used for getting help and giving real-time feedback
  • Green = OK, ready to continue
  • Red = too fast, don’t understand, computer says no etc
• Please interrupt me to ask questions
• Peer learning
  • During exercises, please help each other as required
  • Please try to be quiet during worked examples so everyone can hear

What is a version control system?

• Version control is a piece of software which allows you to record and preserve the history of changes made to directories and files.
• If you mess things up, you can retrieve an earlier version of your project.

Storing versions without VCS

• Save a copy elsewhere?
• Save with a different name?
• How do you name different versions?
• What’s different between them?
• Many of copies of nearly-identical but critically different files.

Why use version control

To store versions properly

• VCS treats files as one project - one current version on disk, previous versions and variations are saved in a repository
• VCS starts with a base version of the project, and only saves the subsequent changes you make
• In order to save a new revision, a commit message is required, which explains why the changes were made.

Changes are saved sequentially

Different versions can be saved

Multiple versions can be merged

Why use version control?

• Restore previous versions
• Understand what happened
• Backup
• Collaboration

Before we get started

• Example scenario
• Text files vs binary files
• Git vs GitHub

Check setup was a success

ssh -T git@github.com

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

Open the notes

https://gcapes.github.io/git-course

Why learn the commands?

The staging area

Exercise 1

Create your own repo

http://gcapes.github.io/git-course/03-history

Switching to a previous commit: “detached HEAD”

Branches

Three exercises on branching

http://gcapes.github.io/git-course/06-branching/

Revert

Create a new commit

Reset

Delete commit(s)

Exercises on remote collaboration

https://gcapes.github.io/git-course/10-remote-collaboration

Feedback form

Rebasing

Merge vs rebase

Standard merge

Rebase onto master

(FF) merge after rebase

Forks and Pull Requests

Send me a PR!

https://gcapes.github.io/git-course/13-pull-requests/#send-me-a-pull-request