Git Overview

What is Git?

• Version control for Programmers

• Like Microsoft Word “Track Changes” feature with superpowers

• Makes it easy for programmers to collaborate and work on the same codebase

• SVN (subversion) and CVS are other version control programs (Git is the most popular)

What is Github?

• Web-based Git repository hosting service

• Built on top of git

• Home to +90% of all open source projects

• Morphed into a “social network” for developers

Vocabulary

• Repository
• Commit
• Branch
• Merge
• Push
• Pull
• Fork
• Clone
• Pull Request

Respository

• Most basic element of GitHub

• A repository contains all of the project files

• Stores each file’s revision history

• Repositories can have multiple collaborators and can be either public or private.

Commit

• A “revision”, is an individual change to a file (or set of files)

• Git’s version of “saving”

• Commits usually contain a commit message which is a brief description of what changes were made

Branch

• Parallel version of a repository

• It is contained within the repository, but does not affect the primary or master branch allowing you to work freely without disrupting the “live” version.

• When you’ve made the changes you want to make, you can merge your branch back into the master branch to publish your changes

Merge

• Merging takes the changes from one branch (in the same repository or from a fork), and applies them into another

• This often happens as a Pull Request (which can be thought of as a request to merge)

Push

• Refers to sending your committed changes to a remote repository such as GitHub.com

• For instance, if you change something locally, you’d want to then push those changes so that others may access them

Pull

• Pulls code from a remote repository and merges it with code in your local repository (on your computer)

Fork

• A fork is a copy of a repository. Forking a repository allows you to freely experiment with changes without affecting the original project

• Most commonly, forks are used to either propose changes to someone else’s project or to use someone else’s project as a starting point for your own idea

Clone

• Copies a remote repository down to your computer and creates a link between the two

Pull Request

• Pull requests are proposed changes to a repository submitted by a user and accepted or rejected by a repository’s collaborators.
• Pull requests each have their own discussion forum. See Using Pull Requests.
• Used to perform “Code Reviews” of other developers’ work