Open source version control management

GIT is a distributed revision control system with an emphasis on speed.
GIT was initially designed and developed by Linus Torvalds for Linux kernel development.
Later on, GIT became the de facto standard in the open source community.

The main design goals behind GIT are:-

·         Support for distributed workflow

·         Very high performance

·         Very strong safeguards against corruption

GIT is free software. It is distributed under the terms of GNU General Public License v2. The GIT provides only the basic functionality for SCM operations. It can be seen as a versioning file-system. GIT does not have any notion of users or access rights. Nor it has any graphical user interface. All these are built on top of GIT by additional tools, like Gerrit.

Let's get started:-
Initializing the build environment

64-bit systems:

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$ sudo apt-get install git-core gnupg flex bison gperf build-essential zip curl zlib1g-dev libc6-dev lib32ncurses5-dev ia32-libs x11proto-core-dev libx11-dev lib32readline5-dev lib32z-dev libgl1-mesa-dev
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More information on initializing the build environment can be found at:-
http://source.android.com/source/initializing.html

Download the GIT Source
Use your favorite package installer to install git-core and gitosis packages:
sudo apt-get -y install git-core

Installing Repo
Repo is a tool that makes it easier to work with Git in the context of Android. For more information about Repo
To install, initialize, and configure Repo, follow these steps

Make sure you have a bin/ directory in your home directory, and that it is included in your path:

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$ mkdir ~/bin
$ PATH=~/bin:$PATH
$ curl http://android.git.kernel.org/repo > ~/bin/repo
$ chmod a+x ~/bin/repo
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After installing Repo, set up your client to access the android source repository:-

Create an empty directory to hold your working files:

Run repo init to bring down the latest version of Repo with all its most recent bug fixes. We must specify a URL for the manifest, which specifies where the various repositories included in the Android source, will be placed within your working directory.

$ repo init -u git://hostname/local/platform/manifest.git

To check out a branch other than "master", specify it with -b:

When prompted, configure Repo with your real name and email address. To use the Gerrit code-review tool, you will need an email address. Make sure this is a live address at which you can receive messages.

A successful initialization will end with a message stating that Repo is initialized in your working directory. Your client directory should now contain a .repo directory where files such as the manifest will be kept.

To pull down files to your working directory from the repositories as specified in the default manifest, run $repo sync

Let’s learn something about manifest file, how it works and what it contains?

What is a Manifest file??
It’s a xml file, which contains information related to:-
·         Remote
·         Revisions
·         Project path
·         Project name


Manifest file is a xml file which contains all the information about:-
Projects:-
Which are the git projects that have to be synced, where those projects are located, which revision of those git projects should be picked while syncing to local directory.

Remote:-
Points to the generic path of the git repositories.

Revision: -
Specifies which branch or tag or commit needs to be picked up while syncing.

Useful Links to explore mode on GIT:-
http://www.gitref.org
http://www.kernel.org/pub/software/scm/git/docs/user-manual.html
 http://progit.org/book/
 http://git-scm.com/
http://www.github.com