WArchive [DRAFT] A Hitchhikers Guide To Git: Exodus

Introduction

What is This?

This post is the second of a series of three blog posts that tries to provide a gentle introduction to git. It follows the premise:

If you know how a thing works, you can make it do what you want it to.

I'm assuming you either read the first part (TODO LINK), Genesis, or skipped it because you know all thats done in there.

Overview

Here, again, the overview, we're doing the second part today.

Genesis

Genesis (i.e. "Creation" or "Beginning"), covered some very basic things:

• Configuring git so you can use it how you want. (Basic, aliases)
• Creating your git repository (play god once!)
• Creating your first git commits.
• Learning what the repository is and where commits get stored.
• Browsing through history.
• Ignoring files.

Exodus

This tutorial, Exodus (i.e. "going out") covers:

• Storing temporary changes without committing.
• Navigating commits in git.
• Sharing commits to a remote place.
  • Locally (huh, that's sharing?)
  • Via email
  • To a server
  • To a client
• Working with others (i.e. non-linear).
  • Join things.
  • Linearize things.
• Writing good commits.
• Editing commits. (Actually not editing but it feels like that.)

Apocalypse

Apocalypse (i.e. "uncovering") will try to uncover some more advanced features of git, finally freeing your mind from your non-versioned filesystem:

• Finding more information about code.
• Finding causes of bugs in git.
• Reverting commits.
• Reviewing commits.
• Travelling though time and changing history (you want me to believe you've never wanted to do that?)
• Getting back lost things.
• Let git do things automatically.

Disclaimer

I wrote this tutorial to the best of my knowledge and experience, if you spot an error or find something important is missing, be sure to drop me a message!

Preparation...

Don't forget your towel, whatever you do! If you still don't have one, go, get one! Now!

Branching

What Is a Branch?

You've waited long for this in the first tutorial, desperately - and I failed you. I'm sorry, wanted to cover the groundwork first. So let's get to this:

Do you recall that weird HEAD file in the .git directory I promised to explain a bit more last time? That HEAD file was a pointer to the current commit which contained the files we compare our filesystem with. Furthermore we saw that this HEAD file actually didn't reference the commit directly. It referenced some master file:

$ cat .git/HEAD 
ref: refs/heads/master

This file, refs/heads/master, contained just the ID of the current commit. This file is the master branch.

So to summarize: a branch is nothing more than a pointer (i.e. alias) to some commit.

How Can We Use Branches?

Let's try out the git branch command:

$ git branch
* master

The branch command shows us what branches are available. Obviously there is this master branch there - which corresponds finely to the refs/heads/master file.

TODO CHECKOUT

Committing on a Branch

When making a commit on a branch the current branch gets updated automatically, i.e. it points to the new commit.

TODO

Exodus (i.e. "going out") will cover:

Store temporary changes without committing.
Navigating commits in git.
Sharing commits to a remote place.
    Locally (huh, that's sharing?)
    Via email
    To a server
    To a client
Working with others (i.e. non-linear).
    Join things. git cat-file -p
    http://www.quora.com/How-does-Git-merge-work
    Linearize things.
Writing good commits.
Editing commits. (Actually not editing but it feels like that.)