Git is a distributed version control system (VCS) that has become the de facto standard for software development projects, both large and small. It was created by Linus Torvalds, the creator of the Linux operating system, in 2005 to manage the development of the Linux kernel. Git's primary function is to enable multiple developers to work on a single project without overwriting each other's changes.
Git is a tool that is used to track changes in source code during software development. It is designed to handle everything from small to very large projects with speed and efficiency. Git is easy to learn and has a tiny footprint with lightning fast performance. It outclasses SCM tools like Subversion, CVS, Perforce, and ClearCase with features like cheap local branching, convenient staging areas, and multiple workflows.
Definition of Git
Git is a distributed version control system, which means that the entire codebase and history is available on every developer's computer, which allows for easy branching and merging.
The core of Git was originally written in the programming language C, but Git has also been re-implemented in other languages, such as Java, Ruby and Python. The Git project chose to use GPLv2 to guarantee your freedom to share and change free software---to make sure the software is free for all its users.
Key Features of Git
Git has a number of key features that set it apart from other version control systems. These include its speed, data integrity, and support for distributed, non-linear workflows.
Git's data model ensures high integrity of your data by applying a cryptographic hash function (SHA1) to your files and directories. This makes it virtually impossible to change the contents of a file, the dates, or the commit message and re-save it without Git knowing about it.
Git Terminology
There are several key terms that are important to understand when using Git. These include repository, commit, branch, merge, and pull request.
A repository is a directory where Git has been initialized to start version controlling your files. A commit, or "revision", is an individual change to a file (or set of files). It's like when you save a file, except with Git, every time you save it creates a unique ID that allows you to keep record of what changes were made when and by who.
History of Git
Git was created by Linus Torvalds in 2005 for development of the Linux kernel, with other kernel developers contributing to its initial development. It is named after the British English slang word for a stupid or unpleasant person, which Torvalds said he was when he decided to develop this project.
Since its birth in 2005, Git has evolved and matured to be easy to use and yet retain these initial qualities. It's incredibly fast, it's very efficient with large projects, and it has an incredible branching system for non-linear development.
Git and GitHub
While Git is a command line tool, GitHub provides a Web-based graphical interface. It also provides access control and several collaboration features, such as a wikis and basic task management tools for every project.
GitHub is a for-profit company that offers a cloud-based Git repository hosting service. Essentially, it makes it a lot easier for individuals and teams to use Git for version control and collaboration.
Use Cases of Git
Git is used in both commercial and open-source software development environments. Its flexibility, speed, and robustness have made it the leading choice for version control software among developers.
Git's distributed nature makes it an ideal choice for collaborative projects. Each developer has a complete copy of the project repository on their local machine, which allows them to work independently of the central repository.
Git in Open Source Projects
Git is widely used in open source projects. This is largely due to its distributed nature, which allows anyone to contribute to the project without needing write access to the central repository.
Open source projects that use Git include the Linux kernel, Ruby on Rails, and the Gnome desktop environment. Git's popularity in the open source community also led to the creation of GitHub, a web-based hosting service for Git repositories.
Git in Commercial Software Development
Git is also widely used in commercial software development. Companies like Google, Microsoft, and Facebook use Git to manage their codebases.
Commercial software development teams often use Git in conjunction with continuous integration/continuous delivery (CI/CD) systems. These systems automate the process of testing and deploying software, and they often rely on Git's branching and merging features.
Specific Examples of Git Usage
Let's take a look at some specific examples of how Git is used in real-world software development.
One common use case for Git is managing a web application's codebase. The developers each have a copy of the codebase on their local machines, and they use Git to sync their changes with the central repository.
Branching and Merging
One of the key features of Git is its support for branching and merging. This allows developers to create a new "branch" of the codebase, make changes, and then "merge" those changes back into the main codebase.
For example, a developer might create a new branch to add a new feature to the application. They would then use Git to merge that branch back into the main codebase when the feature is complete.
Collaboration and Pull Requests
Git also supports collaboration through the use of "pull requests". A pull request is a way of proposing changes to the codebase. Other developers can review the changes, discuss them, and then merge them into the main codebase.
For example, a developer might make changes to the codebase and then submit a pull request. The other developers would review the changes, make any necessary comments, and then merge the changes if they are approved.
Conclusion
Git is a powerful tool for software development. Its speed, flexibility, and robustness have made it the leading choice for version control among developers.
Whether you're working on a small personal project or a large commercial software development team, Git has the features and performance you need to manage your codebase effectively.