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<h2>Introduction to the Git Reference</h2>

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<p>

This is the Git reference site. This is meant to be a quick

reference for learning and remembering the most important and

commonly used Git commands. The commands are organized into

sections of the type of operation you may be trying to do, and

will preset the common options and commands needed to accomplish

these common tasks.

</p>

<p>

Each section will link to the next section, so it can be used

as a tutorial. Every page will also link to more in-depth

Git documentation such as the offical manual pages and relevant

sections in the <a href="http://progit.org">Pro Git book</a>,

so you can learn more about any of

the commands. First, we'll start with thinking about source code

management like Git does.

</p>

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<h2>How to Think Like Git</h2>

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<p>

This first thing that is important to understand about Git is

that it thinks about version control very differently than

Subversion or Perforce or whatever SCM you may be used to. It

is often easier to learn Git by trying to forget your assumptions

about how version control works and try to think about it in the

Git way.

</p>

<p>

Let's start from scratch. Assume you are designing a new source

code management system. How do you do basic version control before

you used a tool for it? Chances are that you simply copied your

project directory to save what it looked like at that point.

</p>

<pre> $ cp -R project project.bak </pre>

<p>

That way, you can easily revert files that get messed up later, or

see what you have changed by comparing what the project looks like

now to what it looked like when you copied it.

</p>

<p>

If you are really paranoid, you may do this often, maybe putting the

date in the name of the backup:

</p>

<pre> $ cp -R project project.2010-06-01.bak </pre>

<p>

In that case, you may have a bunch of snapshots of your project that

you can compare and inspect from. You can even use this model to

fairly effectively share changes with someone. If you zip up your

project at a known state and put it on your website, other developers

can download that, change it and send you a patch pretty easily.

</p>

<pre>

$ wget http://sample.com/project.2010-06-01.zip

$ unzip project.2010-06-01.zip

$ cp -R project.2010-06-01 project-my-copy

$ unzip project.2010-06-01.zip

$ cd project-my-copy

$ (change something)

$ diff project-my-copy project.2010-06-01 > change.patch

$ (email change.patch)</pre>

<p>

Now the original developer can apply that patch to their copy of the

project and they have your changes. This is how many open source

projects have been collaborated on for several years.

</p>

<p>

This actually works fairly well, so let's say we want to write a tool

to make this basic process faster and easier. Instead of writing a tool

that versions each file individually, like Subversion, we would probably

write one that makes it easier to store snapshots of our project without

having to copy the whole directory each time.

</p>

<p>

This is essentially what Git is. You tell Git you want to save a snapshot

of your project with the <code>git commit</code> command and it basically

records a manifest of what all of the files in your project look like at

that point. Then most of the commands work with those manifests to see

how they differ or pull content out of them, etc.

</p>

<center><img src="/images/snapshots.png"/></center>

<p>

If you think about Git

as a tool for storing and comparing and merging snapshots of your project,

it may be easier to understand what is going on and how to do things

properly.

</p>

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<p><a href="/creating">On to Getting and Creating Projects &#187;</a></p>