Revision Control Using Git

The Practical Way

Created by Chang Yu-heng (張昱珩)

2014-06-09

What is a revision control system?

It's a software which let you manage your project

much easier

Without it...

Anything you want to find

becomes a challenge to your memory

And it's only about a tiny project

So we need a powerful tool

And the most powerful revision

control tool right now is

Git

Who's using Git?

OK

What can Git do?

1. Anotate each line

Who did that?

or

Which version did that?

2. Merge

Let's do merge

Git Gives You...

Git Can Do It For You

If There's Not Any Confliction

Usually Correct

But...

hello.py still doesn't print "hello"

Forget it!

3. Commit

A commit is a snapshot of your repository.

The direction of the arrow means: "derived from".

The graph means B derived from A.

Each commit only knows its parent(s).

It has no idea about its child(rden).

Cause the child(ren) not even born yet. So it cannot point to its child(ren).

If you want to do this:

You have to update B on each time a new child of B being born.

Doesn't make sense.

Look inside the commits

4. Branch

Branches are just pointers which point to specific commits

"master" is a branch which points to commit "f30ab".

Different branches can point to the same commit.

So just branch it. It's cheap.

"HEAD" represents which branch/commit your are at now.

To "checkout" another branch/commit is easy. Just move your "HEAD".

With branches, you can keep different version of your work in the same repository.

Summary

Thanks for your attention