A gentle introduction to the awesomeness of Git as presented a RubyFest, may 2009.

1. GIT BASICS
by Ariejan de Vroom – Kabisa ICT

2. WHAT THE GIT?!
“I'm an egotistical bastard, and I name all my projects after
myself. First Linux, now git.” – Linus Torvalds

3. GET GIT!
http://git-scm.com/

5. SURVEY
• Who is NOT using version control?
• SubVersion?
• Anything else?

6. WHY GIT?!
• Distributed Repositories
• Non-linear Development
• Very fast branching and merging
• Toolkit Design
• Scales
• Cryptographic authentication of history.

7. LET’S ROCK!
~/gitbasics $ git init
Initialized empty Git repository
in /Users/ariejan/gitbasics/.git/

8. LET’S ROLL!
~/gitbasics $ git clone
git@github.com/ariejan/gitbasics.git

9. ~/gitbasics $ echo quot;Live long and prosperquot; > README
~/gitbasics $ git add README
~/gitbasics $ git commit -m quot;Added READMEquot;
[master (root-commit)]: created 8e60b09: quot;Added READMEquot;
1 files changed, 1 insertions(+), 0 deletions(-)
create mode 100644 README

10. WHAT JUST HAPPENED?
~/gitbasics $ git log
commit 8e60b09d3082e9473944075cc01b3b67bb97d5c3
Author: Ariejan de Vroom <ariejan@ariejan.net>
Date: Mon May 11 21:51:24 2009 +0200
Added README

11. HOW GIT WORKS
Working Directory
git add
Staging Area
git commit
Repository

12. WORKFLOW
• Hack! ( TextMate, vim, ... )
• Stage your changes ( git add )
• Review your changes ( git status | diff )
• Commit (locally) ( git commit )
• Repeat

13. USING BRANCHES
• Very, very fast
• Keep different code paths separate
• Try new things
• Atomic merges!

14. SURVEY
• How many of you use branching?
• Do you work exclusively on trunk/master?
• NEVER work on trunk/master?

15. BRANCHING
c1 c2 c3 c4
c5 c6

16. LET’S BRANCH!
~/gitbasics $ git checkout -b new_feature
Switched to a new branch quot;new_featurequot;
~/gitbasics $ git branch
master
* new_feature
~/gitbasics $ git checkout master
Switched to branch quot;masterquot;
~/gitbasics $ git branch -d feature3
Deleted branch feature3

17. MERGING
• Merge two branches together
• Add new features
• Add bugs fixes

18. MERGING
c1 c2 c3 c4 c7
c5 c6

19. MERGING
~/gitbasics $ git checkout master
Switched to branch quot;masterquot;
~/gitbasics $ git merge new_feature

20. REBASING
• Bring a branch up-to-date
• Rebasing is rewriting history!
• Don’t use rebasing on a branch you’re
sharing!

21. REBASING
c1 c2 c3 c4
c3’ c4’ c5 c6

22. REBASING
~/gitbasics $ git checkout new_feature
Switched to branch quot;new_featurequot;
~/gitbasics $ git rebase master

23. REMOTE
• Store and share your code!
• github.com
• gitosis ( self-managed over SSH )

24. PUSH
~/gitbasics $ git add origin git@github.com/ariejan/
gitbasics.git
~/gitbasics $ git push origin master

25. FETCH / PULL
~/gitbasics $ git fetch origin
~/gitbasics $ git pull origin master

26. WORKFLOW
Working Directory
add
Staging Area
checkout merge
commit
Repository
pull
push fetch
Remote

27. TAGGING
• Mark a point in history
• Optionally sign it cryptographically with
GnuPG

28. TAGGING
v1.0
c1 c2 c3 c4

29. TAGGING
~/gitbasics $ git tag -a -m quot;Tag v1.0quot; v1.0
Switched to branch quot;new_featurequot;
~/gitbasics $ git tag
v1.0
~/gitbasics $ git push --tags

30. BISECTING
• Binary search for a bad commit
• Find out where it when wrong (and who to
blame)

31. BISECTING
v1.0 Good or Bad?
c1 c2 c3 c4 c5 c6 c7

32. BISECTING
~/gitbasics $ git bisect start
~/gitbasics $ git bisect bad
~/gitbasics $ git bisect good v1.0
~/gitbasics $ git bisect bad | good
~/gitbasics $ git bisect reset
~/gitbasics $ git bisect start HEAD v1.0

33. RELEASE
MANAGEMENT
• Manage your DTSP environments
• Branches to the rescue!

34. RELEASE
MANAGEMENT
~/gitbasics $ git branch production master
~/gitbasics $ git push origin production
~/gitbasics $ git checkout --track -b production origin/production

35. RELEASE
MANAGEMENT
~/gitbasics $ git checkout production
~/gitbasics $ git rebase master
~/gitbasics $ git push origin production

36. TAGGING RELEASES
~/gitbasics $ git checkout master
~/gitbasics $ git tag -a -m quot;Tag v1.0.3quot; v1.0.3
~/gitbasics $ git push --tags
~/gitbasics $ git checkout production
~/gitbasics $ git rebase v1.0.3
~/gitbasics $ git push origin production

37. THE STASH
• Stash away uncommited changes
• Ideal for quick bug fixes!

38. THE STASH
~/gitbasics $ git status
# modified: README
~/gitbasics $ git stash
~/gitbasics $ git status
nothing to commit
# Hack, stage, review, commit, etc.
~/gitbasics $ git stash pop
~/gitbasics $ git status
# modified: README

39. CONFLICTS
• Conflicts happen
• Git is clever
• Easy to resolve manually
• Merges are atomic!

40. CONFLICTS
~/gitbasics $ git merge awesome_feature
Auto-merged README
CONFLICT (content): Merge conflict in README
Automatic merge failed; fix conflicts and
then commit the result.
~/gitbasics $ vim README
~/gitbasics $ git add README
~/gitbasics $ git commit -m “fixed merge
conflict”

41. .GITIGNORE
• Specify which files to keep out of git
• Location specific configuration
• Generated files
• Binary build files

42. .GITIGNORE
~/gitbasics $ cat .gitignore
config/database.yml
log/*.log
tmp/*
public/system/uploads/*

43. SURVEY
• Who is going to try Git?
• Stick with SubVersion?

44. WE’RE HIRING!
AWESOME CODERS
recruitment@kabisa.nl

45. THANKS!
Slides will be posted to http://slideshare.net/ariejan
Contact me at ariejan@kabisa.nl