Open Source Collaboration
with Git and GitHub
by Benjamin Young
adapted 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 io n Co ntro l
c o uld s a v e y o ur
life .

Or a t le a s t y o ur
jo b/pro je c t/ide a /
s a nity /g pa

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
main.c
457aef 93f f 7f f bb289f 7e1384f 900679eac f 044a

Git Internals: Trees

Git Internals: Commits

Git Internals: Commits

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

The Staging Area

What's changed?
git status
On 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 diff
diff --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
branchna
me
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
branchna
me
remotes/server/na
me
HEAD

Local vs. Remote

Multiple Workflows

Centralized

Integration Manager

Benevolent Dictator

Where to Share

=

Other Hosting Options
• Public Only • Public and Private
– repo.or.cz – GitHub.com
– Gitorious.org – CodaSet.com
• Private Only
– Unfuddle.com
– codebasehq.com

How to Contribute
1. Fork a repository at GitHub
2. Clone and connect your local repository
3. Write tests, implement functionality
4. Commit your local changes
5. Push your changes to your fork
6. Make a pull request
7. Profit!!

git log
• Kudos to Sc o tt Cha c o n 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.to byoung@bigbluehat.com
http://litanyagainstfear.com http://bigbluehat.com