Introduction to Git

  • Version control is like an unlimited ‘undo’.
  • Version control also allows many people to work in parallel.

Why use Git?

Why using Git will make you a better researcher:

  • You know you can always go back to a working version of your code
  • You will have a way of showcasing your projects
  • You will be able to distribute your code to others
  • You will be able to modify other peoples’ code and make contributions to it
  • You will have a digital lab notebook

Fundamental concepts

  • Commits are snapshots of a repository.
  • We can have a copy of our repository in a different location, called a remote. We can send (“push”) and receive (“pull”) changes from the remote to interact with others’ work, and also to back up or update our local copy.
  • The staging area is where we keep track of the changes that we are going to commit, that is, which are going to be written in the repository history.
  • Branches are isolated timelines of a repository, where people can work in parallel.

Your first Git repository

  • git init initializes a repository.
  • Git stores all of its repository data in the .git directory.

Tracking changes

We learned several new commands. Let’s take note of them:

  • git init initialises a Git repository, which is contained within the hidden .git directory.
  • git status shows the current state of the repository, such as which files have been changed.
  • git add adds a file to the staging area, where we gather all of the changes that will be committed.
  • git commit writes the changes to history, permanently recording them to the repository.
  • git log shows the list of commits in the repository.
  • git diff shows the changes between the last commit and the current repository, showing how files have been changed.

Remotes: pushing and pulling

  • The git push command pushes local changes to the GitHub remote. Before running it, we must set our remote to the correct URL.
  • The git pull command pulls remote changes to our local repository. We need to run it to sync our local repository to the newest updates on the remote.
  • The git remote command is used to manage remotes, such as setting the GitHub URL, to view the configured remotes, and other actions.

Cloning a repository

  • git clone copies a remote repository to our local repository.
  • git checkout allows us to move between commits – back and forth through a repository’s timeline.
  • HEAD indicates the current state of the repository. HEAD~1, HEAD~2 refer to one or two commits before the current
  • We cannot push to a remote repository if we do not have access to it.

Forking a repository

  • Forking a repository creates a new remote that we have control over.
  • We can update the remote on our local repository using git remote set-url <REMOTE_NAME> <REMOTE_URL>.
  • Pull requests are a way of collaborating that allows other people to merge our changes into their repository.
  • Conflicts are when two commits modify the same parts of a file. We must resolve conflicts before merging them. This can be done by creating a new commit.
  • Conflicts are denoted by <<<, >>> and === characters around the conflicting lines.

Tips and best practices

  • There are a number of strategies to incorporate Git into your day-to-day work.
  • The learning curve can seem steep at first, but with time you will understand how valuable Git is and it will become easier and easier to use.
  • GitHub offers numerous features that make adopting Git easier, and enable you to showcase your projects.
  • There are a few best practices which will dramatically improve your efficiency with Git.