This was a presentation I gave at the 2012 NorthEast PHP conference, in Cambridge, MA.

1. Getting Into Git
8/11/2012
Rick Umali
rickumali@gmail.com
@rickumali
http://tech.rickumali.com/
This presentation is on Google Drive at:
http://sn.im/git-talk-2012
There you can read the 'speaker notes' for this
presentation. You can also provide feedback at:
https://joind.in/6830

2. Questions I Plan to Answer
What is source control?
What is the big deal with Git?
Can you show me a little Git?
Commits. Branches. Merges. Remote repos.

3. What is Source Control?
Source code control is the most important
practice a coding professional can do.
A mechanism to track changes in source code.
Used for version history, auditing, and
recovery.

4. Revision Control Example: Wiki

5. Revision Control Example: Git
This is what we'll be trying.

6. Git
Git is an open source, distributed version
control system designed for speed and
efficiency.
● Freedom
● No "server" required
● Unique architecture

7. Installing Git
http://git-scm.com/book/en/Getting-Started-Installing-Git
The installation is very easy!

8. Warning: Command Line Ahead

9. Our Example: A Basic Drupal Module

10. Creating a "Repository"
Let's pretend we're developing a Drupal
module.
% cd web/sites/all/modules
% mkdir dumpstamp
% cd dumpstamp
% git init
"git init" creates the entire Git repository. No
server interaction required!

11. Committing Your First File
To 'commit' means 'to save the state' of your
work. You must first 'add' this change to the
'staging area'.
% vi README.txt
% git add README.txt
% git commit -m "First commit. README file."
Use 'git help' to learn all the switches. -m
stands for message.

12. Looking at the Repository History
% git log
Each 'commit' contains an ID, along with the
author information from earlier, and a time
stamp.
% gitk
GUI tools can help you visualize the 'repo.'

13. Adding More Files
% vi dumpstamp.info dumpstamp.module
% git status
% git add .
% git commit
This second commit saves the work of adding
two files by using 'git add .'.
The .module and .info files are the two
required files for every Drupal module.

14. Enabling Our Drupal Module
% drush pm-info dumpstamp
% drush pm-enable dumpstamp

15. Examining Changes to Files
% vi dumpstamp.module
% git status
% git diff
% git add dumpstamp.module
% git commit
% git log
The above is a typical 'workflow'.
Git offers suggestions and hints as you use it.

16. Doing More Changes
% vi dumpstamp.module
% git diff
% git commit -a
Or even:
% git commit -a -m "Commit message."
Another typical 'workflow'.

17. Looking at the Log Again
The history can be examined different ways.
% git log
% git log --format=short
% git log --format=oneline
% git log --oneline

18. Revisiting History
You can 'revisit' any point of your history.
% git checkout SHAID
Every commit is known by its SHA ID.
This is the first step in making a branch! (Use
git checkout master to revert.)

19. Branching and Merging Next, But...
What we have covered so far is probably 70-
80% of what you will do with git.
Adding and committing files are the heart of
git (and any version control system).

20. Git encourages experimentation, by making
branching very easy.
Branching

21. Branching: git branch
% git branch BRANCH SHA1
% git checkout BRANCH
Make some edits on a change below the
master, then commit.
git branch makes a branch from the branch
you're on (default branch is 'master').

22. Branching: Starting State
SHA 1Amaster
NOTE: 'master' is a branch that's created 'by default'.

23. Branching: Make Some Changes
SHA 1A
SHA 2Bmaster
git commit

24. Branching: Making a Branch
SHA 1A
SHA 2Bmaster
branch1
git branch "branch1" SHA1A
git checkout "branch1"
OR git checkout -b branch1 SHA1A

25. Branching: Changes on the Branch
SHA 1A
SHA 2Bmaster branch1SHA 3C
(Make changes in "branch1".)
git commit

26. Visualizing the Branches

27. Merging
Bringing two branches together.
First 'checkout' the branch you want to merge
into (typically master), then 'merge' the
branch.
% git checkout master
% git merge BRANCH

28. Merging: Starting State
SHA 1A
SHA 2Bmaster branch1SHA 3C

29. Merging: Two Steps
SHA 1A
SHA 2B
master
branch1SHA 3C
SHA 4D
git checkout master
git merge branch1

30. Merging: The Hard Part
Manual 'merging' may be required.

31. Visualizing the Merge

32. Whew!

33. Remote Branches
You can 'browse' public Git repositories for
code that you want to examine or use.
You can upload a local Git repository to a
public Git repository.

34. Common Public Git Repositories

35. Browsing and Grabbing Code
git clone git@github.com:rickumali/RickUmaliVanityWebsite.
git

36. Uploading Code (to Github)
Create a key pair on your machine.
Create a repository (on Github).
Add a 'remote' (via git remote add).
Upload your code (via git push).

37. Creating a Key Pair

38. Creating a Repository

39. Adding a Remote, then Upload

40. After An Upload (to Github)
git clone git@github.com:rickumali/DumpStamp.git

41. Next Steps
Install Git.
Commit your code changes frequently.
Log verbosely (in commit messages).
Experiment (branch) often.

42. Getting Into Git
Rick Umali
rickumali@gmail.com
@rickumali
http://tech.rickumali.com/
Thank you!

43. Resources
http://git-scm.org/
Both "Pro Git" book, and Git reference
http://gitref.org/
A "quicker" Git reference
http://www-cs-students.stanford.edu/~blynn/gitmagic/
"Friendlier" Git walk-through (git magic).
http://drupal.org/node/803746
A workflow for using Git with Drupal.
http://www.mail-archive.com/dri-devel@lists.
sourceforge.net/msg39091.html
Linus on "clean history."

44. Resources
http://www.youtube.com/watch?v=4XpnKHJAok8
Linus Torvalds (Git creator) (May '07)
http://www.youtube.com/watch?v=8dhZ9BXQgc4
Randal Schwartz (Perl expert and Git old-timer) (Oct
'07)
http://www.youtube.com/watch?v=ZDR433b0HJY
Scott Chacon (Pro Git author) (July '11)