Why and How — Git and GitHub

Published in

The Startup

7 min readJun 14, 2020

What’s a version control system?

What is version control? Essentially, it’s a system that allows you to record changes to files over time, thus, you can view specific versions of those files later on.

A version control system, or VCS, tracks the history of changes as people and teams collaborate on projects together. As the project evolves, teams can run tests, fix bugs, and contribute new code with the confidence that any version can be recovered at any time. Developers can review project history to find out:

Which changes were made
Who made the changes
When were the changes made
Why were changes needed

What’s a distributed version control system?

Git is an example of a distributed version control system (DVCS) commonly used for open source and commercial software development. DVCSs allow full access to every file, branch, and iteration of a project, and allows every user access to a full and self-contained history of all changes. Unlike once popular centralised version control systems, DVCSs like Git don’t need a constant connection to a central repository. Developers can work anywhere and collaborate asynchronously from any time zone.

Why Git?

According to the latest Stack Overflow developer survey, more than 70 percent of developers use Git, making it the most-used VCS in the world. Git is a free and open source distributed version control system.

Git is commonly used for both open source and commercial software development, with significant benefits for individuals, teams and businesses.

Git lets developers see the entire timeline of their changes, decisions, and progression of any project in one place. From the moment they access the history of a project, the developer has all the context they need to understand it and start contributing.
Developers work in every time zone. With a DVCS like Git, collaboration can happen any time while maintaining source code integrity. Using branches, developers can safely propose changes to production code.
Businesses using Git can break down communication barriers between teams and keep them focused on doing their best work. Plus, Git makes it possible to align experts across a business to collaborate on major projects.

What’s a repository?

A repository, or Git project, encompasses the entire collection of files and folders associated with a project, along with each file’s revision history. The file history appears as snapshots in time called commits, and the commits exist as a linked-list relationship, and can be organised into multiple lines of development called branches. Because Git is a DVCS, repositories are self-contained units and anyone who owns a copy of the repository can access the entire codebase and its history. Using the command line or other ease-of-use interfaces, a git repository also allows for: interaction with the history, cloning, creating branches, committing, merging, comparing changes across versions of code, and more.

Through platforms like GitHub, Git also provides more opportunities for project transparency and collaboration. Public repositories help teams work together to build the best possible final product.

Basic Git commands

To use Git, developers use specific commands to copy, create, change, and combine code. These commands can be executed directly from the command line or by using an application like GitHub Desktop or Git Kraken. Here are some common commands for using Git:

git init initialises a brand new Git repository and begins tracking an existing directory. It adds a hidden sub folder within the existing directory that houses the internal data structure required for version control.
git clone creates a local copy of a project that already exists remotely. The clone includes all the project’s files, history, and branches.
git add stages a change. Git tracks changes to a developer’s code base, but it’s necessary to stage and take a snapshot of the changes to include them in the project’s history. This command performs staging, the first part of that two-step process. Any changes that are staged will become a part of the next snapshot and a part of the project’s history. Staging and committing separately gives developers complete control over the history of their project without changing how they code and work.
git commit saves the snapshot to the project history and completes the change-tracking process. In short, a commit functions like taking a photo. Anything that’s been staged with git add will become a part of the snapshot with git commit.
git status shows the status of changes as untracked, modified, or staged.
git branch shows the branches being worked on locally.
git merge merges lines of development together. This command is typically used to combine changes made on two distinct branches. For example, a developer would merge when they want to combine changes from a feature branch into the master branch for deployment.
git pull updates the local line of development with updates from its remote counterpart. Developers use this command if a teammate has made commits to a branch on a remote, and they would like to reflect those changes in their local environment.
git push updates the remote repository with any commits made locally to a branch.

Learn more from a full reference guide to Git commands.

How GitHub fits in

GitHub is a Git hosting repository that provides developers with tools to ship better code through command line features, issues (threaded discussions), pull requests, code review, or the use of a collection of free and for-purchase apps in the GitHub Marketplace. With collaboration layers like the GitHub flow, a community of 15 million developers, and an ecosystem with hundreds of integrations, GitHub changes the way software is built.

How GitHub works

GitHub builds collaboration directly into the development process. Work is organised into repositories, where developers can outline requirements or direction and set expectations for team members. Then, using the GitHub flow, developers simply create a branch to work on updates, commit changes to save them, open a pull request to propose and discuss changes, and merge pull requests once everyone is on the same page.

The GitHub flow

The GitHub flow is a lightweight, branch-based workflow built around core Git commands used by teams around the globe — including ours.

The GitHub flow has six steps, each with distinct benefits when implemented:

Create a branch: Topic branches created from the canonical deployment branch (usually master) allow teams to contribute to many parallel efforts. Short-lived topic branches, in particular, keep teams focused and results in quick ships.
Add commits: Snapshots of development efforts within a branch create safe, revertible points in the project’s history.
Open a pull request: Pull requests publicize a project’s ongoing efforts and set the tone for a transparent development process.
Discuss and review code: Teams participate in code reviews by commenting, testing, and reviewing open pull requests. Code review is at the core of an open and participatory culture.
Merge: Upon clicking merge, GitHub automatically performs the equivalent of a local ‘git merge’ operation. GitHub also keeps the entire branch development history on the merged pull request.
Deploy: Teams can choose the best release cycles or incorporate continuous integration tools and operate with the assurance that code on the deployment branch has gone through a robust workflow.

GitHub and the command line

For developers new to the command line, the GitHub Training team has put together a series of tutorials on Git commands to guide the way. Sometimes, a series of commands can paint a picture of how to use Git:

Example: Start a new repository and publish it to GitHub

First, you will need to create a new repository on GitHub. You can learn how to create a new repository in our Hello World guide. Do not initialise the repository with a README, .gitignore or License. This empty repository will await your code.

# create a new directory, and initialize it with git-specific functions
git init my-repo# change into the `my-repo` directory
cd my-repo# create the first file in the project
touch README.md# git isn't aware of the file, stage it
git add README.md# take a snapshot of the staging area
git commit -m "add README to initial commit"# provide the path for the repository you created on github
git remote add origin https://github.com/YOUR-USERNAME/YOUR-REPOSITORY.git

# push changes to github
git push --set-upstream origin master
git push -u origin master (Alternative)

Fork

One of the ways to copy a repository to your GitHub account is using fork, which is available on GitHub’s website.

Forking a repository essentially copies that project to your online GitHub account. However, to work on that project on your local computer, you must clone the project.

How It All Works

GitHub Student

As a student, you can get access to the GitHub Student Developer Pack, which includes benefits from GitHub as well as other partners. From GitHub, students receive a free micro account with five private repositories. Learn more about the Student Developer Pack here.

To learn more about using Git and GitHub, check out the resources at the following links:

git-scm.com — The main website and documentation for Git

help.github.com — GitHub’s help documentation

https://drive.google.com/file/d/1PYTNys0WwfPfY9BfkYaxQu9cwMsX7rEg/view?usp=sharing— A cheat sheet of Git commands