[git] Working with git by forking

Github is very nice place to collaborate with other programmers.

This post describe how you update to recent code from original project to your project forked from main project.

1. Fork

Fork can be done by press "fork" in github website of target project.

The fork copies current state of target project to your account.

Assume that you have an account "youraccount" and target project name is "targetproject".

If you fork the target project, you can clone the project by following

$ git clone https://github.com/youraccount/targetproject.git

Actually, it was cloned by

$ git clone https://github.com/targetproject/targetproject.git 

So now you can modify the forked project whatever you want.

2. Update from original project

Sometimes original project maintainer adds some features to targetproject repository.
Update can be done as follows. First of all, add targetproject repository as a remote.

$ git remote add upstream http://github.com/targetproject/targetproject.git

This will add original repository as a remote in current (forked) repository.
You can check current remote repository by following.

$ git remote -v

3. Retrieve updated code from upstream

$ git fetch upstream (This will download the code updated.)

$ git branch -va       (This will shows available branches.)

4. Merge

First checkout master to make current branch to head of our forked project

$ git checkout master

This will merge original head to our master.

$ git merge upstream/master 

References

[1] https://help.github.com/articles/syncing-a-fork
[2] http://gun.io/blog/how-to-github-fork-branch-and-pull-request/