Open Source Collaboration with Git and GitHub

by Benjamin Youngadapted from work by

Nick Quaranto

whoami

• President of BigBlueHat– a web manufacturing company– we build web stuff

• We built BlueInk– a content management system

• Building sites since the late 90's– I remember Netscape 3

Ve rs ion Control c ould s a v e your

life .

Or a t le a s t your job/proje c t/ide a /

s a nity /gpa

The Basics

• Keep “backup” copies of files whenever you want

• Restore those copies quickly and easily• Share the files and the change s with other

developers• Integrate their changes into your files

Directed Acyclic Graph

Git Internals: Blobs

457aef 93f f 7f f bb289f 7e1384f 900679eacf 044a

main.c

Git Internals: Trees

Git Internals: Commits

Git Internals: Commits

Giting Started

• mkdir new_proj• cd new_proj• git init• ...do some work...• git add .• git commit

• cd old_proj• git init• git add .• git commit

The Staging Area

What's changed?

git statusOn branch master

# Changed but not updated:

# (use "git add <file>..." to update what will be committed)

# (use "git checkout -- <file>..." to discard changes in working directory)

#

# modified: index.php

#

What's changed? (cont)

git diffdiff --git a/index.php b/index.php

index 9e7353c..1764d3e 100644

--- a/index.php

+++ b/index.php

@@ -24,4 +24,5 @@

require_once 'webroot'.DIRECTORY_SEPARATOR.'index.php';

-?>

\ No newline at end of file

+echo 'an example change';

+?>

Birds Eye View

• git log• gitk

– a graphical view of your repository• GitX

– Mac OS X app for doing the above– also handy for commit review– prettier than gitk

Git Internals: Branches

branchname

HEAD

Branching

Branching

• Another great reason to use Version Control—particularly git

• “Your first idea is never your best idea”• Branches give you the freedom to change

things...whenever

Branching (cont)

• git branch experimental– creates a branch named 'experimental'

• git branch– shows a list of branches:

• git checkout experimental– switch to the new branch

The Staging Area (cont)

• All that happened in the same directory– sort of...

• Your version histories actually in the .git folder

• so, when you checkout a branch git changes all the files outside of .git to match that branches content

• git it?

Put it back together again

• git checkout master• git merge experimental

• if all went well, then your done• if not:

• git mergetool• git commit -a

Git Internals: Remotes

branchname

HEAD

remotes/server/name

Local vs. Remote

Multiple Workflows

Centralized

Integration Manager

Benevolent Dictator

Where to Share

=

Other Hosting Options

• Public Only– repo.or.cz– Gitorious.org

• Private Only– Unfuddle.com– codebasehq.com

• Public and Private– GitHub.com– CodaSet.com

How to Contribute

1. Fork a repository at GitHub 2. Clone and connect your local repository 3. Write tests, implement functionality4. Commit your local changes 5. Push your changes to your fork6. Make a pull request7. Profit!!

git log• Kudos to Sc ott Cha c on who made

– http://git-scm.com– http://whygitisbetterthanx.com

• And to Mic ha e l Ha rtl– for Building the Insoshi Social Network

• Wikipedia too.

nick@quaran.tohttp://litanyagainstfear.com

byoung@bigbluehat.comhttp://bigbluehat.com