The Azimuth Project



Git is a modern distributed versioning system. This means that several people can work on a piece of software or a paper concurrently on their own computers, and then use Git to synchronize their work and create a consolidated version of the files that they changend.

On this page we will explain how to install Git and check out files from another computer, and also provide some further references. This will hopefully help scientists who would like to improve cooperative work over the internet.


Why Git and not, e.g., Subversion?

Git is different from older versioning systems like SVN (Apache Subversion): SVN is a client server system, which means that

  • there needs to be a machine that is the server,

  • everybody can synchronize with the server only.

This means that one can work with SVN only if the server is available, and two people cannot synchronize with each other without also synchronizing with the central server. This has proven to be a disadvantage for large open source software project with developers spread all over the world, so they came up Git instead (actually Git was developed for Linux). Git is a peer to peer software, which means you have a fully functional repository on your local machine, and can synchronized with anybody else when it is appropriate.

This also applies to the versioning system Mercurial, which is a viable alternative to Git.

Installation and Checkout

This chapter will explain how to download Git and checkout the simple online climate model using a computer running Windows.

You can download Git for free from the Git homepage.

For Windows, there is a full installer which is named “Git-1.7.8-preview20111206.exe” as of 8th January 2010. Download the installer and run it. The installer will request that you accept the licence and answer several questions about installation details. For most users it will be okay to accept the default settings, however.

After installation, you will be able to both start “Git GUI” and “Git Bash”. If you start “Git GUI”, you will see this window:

Git GUI screenshot

In order to get the current version of the simple online climate model, we will need to “clone existing repository”. Paste the repository URL “” to the “source” and specify a non-existing folder as “target”:

Git checkout screenshot

Click the “clone” button and voilà: Git should create a local repository with all files in the specified target folder.