Outline

• What are git and github
• How they work
• How can I use them

Definitions

so what??

clear, uh?

Survey

Who already knows Git?

Who knows any of these?

• SVN
• CVS
• Mercurial

Why should I use version control?

Look, it's not useful if I

• Do not have other people working on the code.
• Do not plan on letting others have the code.
• Isn't it an overhead?

Well, have you ever

• made a change to code, realised it was a mistake and wanted to revert back?
• lost code or had a backup that was too old?
• had to maintain multiple versions of a product?

And if you wonder to

• see the difference between two (or more) versions of your code?
• prove that a particular change broke or fixed a piece of code?
• review the history of some code?

Or even

• submit a change to someone else's code?
• share your code, or let other people work on your code?
• see how much work is being done, and where, when and by whom?

And, last but not least

• wanted to experiment with a new feature without interfering with working code?

Version control systems

Local

Centralized

Distributed

About Git

Desing Goals

• Speed
• Simple Design
• Strong support for thousands of parallel branches
• Fully distributed
• Able to handle larges projects like Linux kernel effectively
• Ensure integrity

Git is a filesystem

Git has integrity

• Everything is checksummed
• References are SHA-1

986da33f0edea8f13b8dee427262ffd1bce0a4c4

Git doesn't delete

• generally only adds data
• if you mess up, you can usually recover your stuff
• not for everyone, though

Git states & workflow

Three states

• Modified
• Staged
• Committed
• Pushed?

Workflow

File status lifecycle

About Github

• web-based Git repository hosting service
• offers all of the distributed SCM functionalities of Git
• adds new features

New features

• web-based graphical interface
• desktop & mobile integration
• access control
• pull requests
• and more (wikis, task management, bug tracking, etc.)

Installing Git

Windows

msysgit: https://msysgit.github.io/

Linux

Debian

$ aptitude install git

Ubuntu

$ apt-get install git

Centos

$ yum install git

Arch

$ pacman -S git

OS X

$ brew install git

Also developer tools should be ok...

Configuring Git

Identity

$ git config --global user.name "Peter Parker"$ git config --global user.email peterparker@bitmama.it

Editor

$ git config --global core.editor nano

Colors

$ git config --global color.ui true

Configurations are in ~/.gitconfig

Using Github

Join github

https://github.com/join

Private/Public Key

SSH keys are a way to identify trusted computers, without involving passwords.

https://help.github.com/articles/generating-ssh-keys/

Starting with Git

Initizialize your project

$ git init

Or clone it

$ git clone https://github.com/andou/github-for-dummies.git

What's up?

$ git status

Decide what is relevant

$ git add file1 file2 ...$ git commit

What did I just modify

$ git diff

What happened?

$ git log

I've screwed everything up....

$ git reset

.gitignore

sample

.DS_Store*.log/build//doc/[abc]*.txt.sass-cache
            

• Blank lines or lines starting with # are ignored
• End pattern with slash (/) to specify a directory
• Negate pattern with exclamation point (!)

Remotes

• Other clones of the same repo
• Can be more than one
• There are default remotes for push and pull
• Github is a remote

$ git remote -vorigin	https://github.com/andou/github-for-dummies.git (fetch)origin	https://github.com/andou/github-for-dummies.git (push)

Push to remote

$ git push <remote>  <branch>

Pull from remote

$ git pull <remote>  <branch>

Tags

• specify important points in history
• tipically release points

Lightweight tags

$ git tag v0.0.1

Annotated tags

$ git tag -a v0.0.1 -m 'this is my tag'

Branches

• are "pointers" to commit
• identify streams of development
• they can diverge from each other
• they can be merged

Diverging branches

Merged branches

Merging

• There are different auto-merge strategies
• If it fails, you'll have to fix by hand
• Mark conflicts as resolved and trigger a merge commit

Branch management

Create new branch

$ git branch iss53

$ git checkout -b iss53 master

Switch Branch

$ git checkout iss53

Delete Branch

$ git branch -d iss53

Stashing

Move changes to a separate "stash".

$ git stash save$ git stash list$ git stash apply

Workflow

Progressive stability

Topic branches

References

• Git: http://git-scm.com/
• Github: https://github.com/
• Try git: http://try.github.com/

More references

• CheatSheet
• My shortcodes

Some more...

• Book [for pro]: http://git-scm.com/book/en/v2
• Git Docs: http://git-scm.com/docs
• Deep tutorial

Not enough??

• Y U no ask Linus Torvalds?