Set up your fork

First you follow the instructions for Making your own copy (fork) of marsbar.

Overview

git clone git@github.com:your-user-name/marsbar.git
cd marsbar
git remote add upstream git://github.com/matthew-brett/marsbar.git

In detail

Clone your fork

1. Clone your fork to the local computer with git clone git@github.com:your-user-name/marsbar.git

2. Investigate. Change directory to your new repo: cd marsbar. Then git branch -a to show you all branches. You’ll get something like:

   * master
   remotes/origin/master
   

   This tells you that you are currently on the master branch, and that you also have a remote connection to origin/master. What remote repository is remote/origin? Try git remote -v to see the URLs for the remote. They will point to your github fork.

   Now you want to connect to the upstream marsbar github repository, so you can merge in changes from trunk.

Linking your repository to the upstream repo

cd marsbar
git remote add upstream git://github.com/matthew-brett/marsbar.git

upstream here is just the arbitrary name we’re using to refer to the main marsbar repository at marsbar github.

Note that we’ve used git:// for the URL rather than git@. The git:// URL is read only. This means we that we can’t accidentally (or deliberately) write to the upstream repo, and we are only going to use it to merge into our own code.

Just for your own satisfaction, show yourself that you now have a new ‘remote’, with git remote -v show, giving you something like:

upstream     git://github.com/matthew-brett/marsbar.git (fetch)
upstream     git://github.com/matthew-brett/marsbar.git (push)
origin       git@github.com:your-user-name/marsbar.git (fetch)
origin       git@github.com:your-user-name/marsbar.git (push)