We explain what is GitHub, what GitHub is for, and why GitHub is great. Plus: alternatives to GitHub.
GitHub is, simply, a code visioning repository using the GIT format. What's that now? Okay, you want plain English. GitHub is a web-based service utilised by developers. It is a very good way of using a central hub to work on collaborative coding projects. As such it is good for open source.
What is GitHub?
It is a web-based hosting service for software-development projects which uses the GIT revision-control system. The GIT standard was started by Linus Torvald (yes, he of Linux fame). GitHub is a commercial business, offering both paid plans for private repositories and free accounts for open source projects.
It is very popular and anecdotal evidence suggests that GITHub is taking over the older formats of CVS, SVN and Microsofts offering Visual source safe. Indeed, GitHub claims to have more than 3.4 million users. It true this would make it the largest code host in the world. GitHub itself is mostly used for code, but is also commonly used for non-code types of files such as Final Cut or Word documents. (See also: GitHub cranks delivery speeds, adds analytics.)
There are other GitHub alternatives such as BitBucket. GitLab, and Gitourious are other code-visioning repositories for project using the GIT revision-control system.
Why GitHub is great
GIT's main difference is its distributed nature. Older standards such as SVN have a single repository to which you push changes. With GIT you can have many local repositories to which developers can share to and pull code from. When you are happy you can push to the online repo - in this cast GitHub.
There are other aspects to GIT and GitHub, such as forking This works well for projects where a lot of people can randomly contribute. It can be a good idea to write open source code using GitHub as you can fork the main code. This then becomes your code, which you can then change to fix bugs or add features. You can then ask that the original source code is updated based on your fork. (See also: GitHub growth points to open source's enterprise acceptance.)
Why GitHub is not great
The main down side to using GIT and GitHub is that it is quite a bit more complex than traditional code, or older code-versioning solutions. And, well, that's it really. (See also: How to install Android L now: a beginners step-by-step guide.)