1. Git
An Introduction
K. ARVIND
Overture Networks
December 2013
DRAWS LIBERALLY FROM VARIOUS ONLINE RESOURCES, ESPECIALLY SCOTT CHACON’s EXCELLENT BOOK ON GIT

2. ● What is Git?
● How is Git different?
● Giit conceptual overview
○ Hashes, Repository, Branching
Plan

3. • Distributed Version Control System
• Linux Community
• 2005
What is Git?

4. ● Single server that contains versioned files
● Clients have version being worked on
● Easy to administer
● Single point of failure
● Need connectivity to commit
● Subversion, CVS, Perforce
Centralized VCS

5. Distributed VCS
● Every client has the full repository
● Central repository may also be used
● Local commits followed by push
● Fault Tolerant
● Work off-line

6. Why Git?
● Fast
● Simple
● Branching
● Fully distributed
● Scales well

7. No Deltas!

8. Dog ate cable - No problem!
Nearly every operation is local!

9. Name is a Digest
Git object name = SHA-1 hash of contents
Built-in integrity check

10. Cryptographic Digest

11. Commit Hash: Git Bash
SOME PROPRIETARY INFORMATION REDACTED BELOW

12. Digest “uniqueness” is “real”!
SOME PROPRIETARY INFORMATION REDACTED BELOW

13. Commit Hash - Gitk
SOME PROPRIETARY INFORMATION REDACTED BELOW

14. Commit Hash: TortoiseGitSOME PROPRIETARY INFORMATION REDACTED BELOW

15. Git Objects

16. Commit History

17. Git Repository

18. Git Repository

19. Git repository

20. Branch - Pointer to a commit
● HEAD - points to current branch
● master - default branch

21. No branches added

22. Add a branch
gitbash> git branch testing f30ab
HEAD still points to master

23. Switch to branch
gitbash> git checkout testing
HEAD has moved to testing

24. Commit on branch
testing points to new commit
HEAD still points to testing

25. Switch back to master branch
gitbash> git checkout master
HEAD points to master now

26. Commit on master
Diverging branches - need to merge
later

27. Merge
gitbash> git merge iss53
Preferred alternative: git rebase

28. Pulling remote branches

29. Conclusion
● Conceptual overview
● Many key concepts
● Free resources available online for further
study:
● ProGit by Scott Chacon - http://git-scm.com/book

30. Thank you Scott Chacon!