Git was created by Linus Torvalds in 2005 for development of the Linux kernel, with other kernel developers contributing to its initial development. So it was a kindoff tool for collaborating the code with fellow developers. Its current maintainer since 2005 is Junio Hamano.
Git is a version control system for tracking changes in computer files and coordinating multiple people working with same set of files. It is primarily used for source code management in software development but it can be used to keep track of changes in any set of files. As a distributed revision control system it is aimed at speed, data integrity, and support for distributed, non-linear workflows.
As with most other distributed version control systems,every Git directory on every computer is a full-fledged repository with complete history and full version tracking abilities, independent of network access or a central server.This helps reducing the level of risk of the source code from a single point of failure.
Git is free and open source software distributed under the terms of the GNU General Public License version 2. there are multiple free and paid versionof the implementation of Git. There are various ways a git can be accessed or managed from a client/ user machine. one of the most powerful option is via command line. This is considered the most powerful and most feature rich option to connect and manage local Git repository.
For ease of use of the readers, we are adding a table of most common commands used in managing a Git repository.
Git provides a failry comprehensive documentation at the git site (Here)
There is also a quick referance cheat sheet provided by Git