Git is a distributed version control system that allows software engineers 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.
Git was created by Linus Torvalds in 2005 for development of the Linux kernel, with other kernel developers contributing to its initial development. Its current maintainer since 2005 is Junio Hamano. Git is free and open-source software distributed under the terms of the GNU General Public License version 2.
Definition of Git
Git is a distributed version control system, meaning that the entire codebase and history is available on every developer's computer, which allows for easy branching and merging.
Git is fundamentally a content-addressable filesystem with a VCS user interface written on top of it. It provides strong support for non-linear development, including thousands of parallel branches, cryptographically secure distributed revision tracking, and convenient staging areas.
Version Control System
A version control system (VCS) allows you to track the history of a collection of files. It supports creating different versions of this collection. Each version captures a snapshot of the files at a certain point in time and the VCS allows you to switch between these versions. These versions are stored in a specific place, typically called a repository.
Git is a member of the distributed version control system (DVCS) category. Rather than have only one single place for the full version history of the software as is common in once-popular version control systems like CVS or Subversion (also known as SVN), in Git, every developer's working copy of the code is also a repository that can contain the full history of all changes.
Distributed Version Control System
In contrast to centralized version control systems (CVCSs), distributed version control systems (DVCSs) like Git don't necessarily rely on a central server to store all the versions of a project’s files. Instead, every developer “clones” a copy of a repository and has the full history of the project on their own hard drive.
This copy (or “clone”) has all the metadata of the original. This scenario offers many advantages, including the ability to work offline and not relying on a single location for backups. If the server goes down, the repository can be restored from any of the developer's local repositories.
Explanation of Git
Git stores and thinks about information much differently than these other systems, even though the user interface is fairly similar, and understanding those differences will help prevent you from becoming confused while using it.
Git only adds data, you can’t lose information in transit, and you have your project history at your fingertips if you’re offline or off VPN or your server goes down. And because you have the whole history, you can always go back to exactly the way things were at a certain point in time.
Git's Data Model
The major difference between Git and any other VCS (Subversion and friends included) is the way Git thinks about its data. Conceptually, most other systems store information as a list of file-based changes. These systems (CVCSs) think of the information they keep as a set of files and the changes made to each file over time.
Git doesn’t think of or store its data this way. Instead, Git thinks of its data more like a set of snapshots of a miniature filesystem. Every time you commit, or save the state of your project in Git, it basically takes a picture of what all your files look like at that moment and stores a reference to that snapshot. To be efficient, if files have not changed, Git doesn’t store the file again, just a link to the previous identical file it has already stored.
Git's Initial Development
The development of Git began on 3 April 2005. The project was announced on 6 April, and became self-hosting as of 7 April. The first merge of multiple branches took place on 18 April. Torvalds achieved his goals: on 29 April, the nascent Git was benchmarked recording patches in the time it took BitKeeper to merely start up. On 16 June Git managed the kernel 2.6.12 release.
Since 2005 Git development has been overseen by Junio Hamano, a software engineer who was one of the first to adopt the tool to maintain his own work and contributed several utilities and extensions. He has remained the project's steward since.
Git's Growth and Adoption
Git quickly became popular in the open source community, and businesses began adopting it soon after. In 2008, Git surpassed both Subversion and CVS in popularity among open source developers, and it continues to have widespread adoption in both open source and business contexts today.
Many large organizations have adopted Git, including Google, Facebook, Microsoft, and Twitter. Microsoft's adoption of Git as the version control system for Windows development has been cited as marking Git's acceptance into the "enterprise" software market. In 2012, Microsoft began using Git in their Team Foundation Server product and in 2013 they announced that they were adopting Git as their version control system of choice.
Use Cases of Git
Git is used in both open source and commercial software development environments. Its flexibility, speed, and robustness have made it the version control system of choice for many developers. Git's distributed nature allows developers to work offline and enables easy branching and merging.
Git is also used in DevOps workflows and practices. It is a fundamental tool in the Continuous Integration / Continuous Deployment (CI/CD) pipeline. In addition, Git is often used in conjunction with other tools in the "DevOps toolchain", such as Jenkins, Chef, and Puppet.
Git in Open Source Projects
Git is widely used in open source projects. This is where it started, with the Linux kernel, and it quickly spread to other projects. Today, all of the top open source projects on GitHub use Git. This includes projects like the Linux kernel, Kubernetes, Docker, Ansible, and many others.
Open source developers prefer Git because it allows them to work independently. They can make changes and commit them to their local repository without needing to connect to a central server. When they are ready, they can push their changes to the central repository. This makes Git ideal for open source projects where developers may be spread out across the globe.
Git in Commercial Software Development
Git is also widely used in commercial software development. Companies of all sizes, from small startups to large enterprises, use Git. It is used in a wide range of industries, including technology, finance, healthcare, and more.
Commercial software developers prefer Git because it is fast and efficient. It can handle large codebases and it makes branching and merging easy. This allows developers to work on different features or bug fixes in isolation, without interfering with each other's work. Once a feature or bug fix is complete, it can be merged back into the main codebase.