In this short presentation we discuss about version control in general and the main differences between centralized and distributed version control. We explain the key git concepts including branching, repositories and commits.

1. Version Control Using Git
Christos Mylonas
Senior Software Engineer
Viva Wallet

2. Agenda
• Version Control
• Git Concepts
• Local & Remote Repositories
• Branching
• Lab

3. Version Control

4. What is version control?
• A system that keeps changes to files over time
• Allows collaboration
• View WHAT has been changed
• View WHO has made the changes
• Undoing
• Revert to prior version

5. What about file copies?
• Multiple directories
• Who made what? hmm?
• Sync
• Compare

6. What about file copies?

7. Centralized Version Control
• Everything is stored on a server.
• Checkout -> Edit -> Commit
• Linear development by design
• TFS (<2013), SVN, Perforce, SourceSafe (legendary)

8. Centralized Version Control
Pros
• Monitoring
• Administration
• Avoid conflicts by design
• Easy to understand
Cons
• Single User Editing
• Single Point of Failure
• Requires Connectivity
• Repository on Server

9. Centralized Version Control

10. Distributed Version Control
• No central server.
• All peers have the repository
• Git
• TFS (>2013)

11. Distributed Version Control
Pros
• Repository mirror
• Multiple workflows
• Non linear development
• Peers
• Edit the same files
• Working alone - offline
Cons
• Difficult to master

12. Distributed vs Centralized

13. git
• Linux - Linus Torvalds (~2005)
• Bitkeeper fork
• Goals: Speed, Branches, Distributed
• File based : Everything exist locally
• Git stores snapshots not differences
• No network required (but we can do almost everything)
• SHA-1 hash : integrity + naming things
• command line, full clients, libraries

14. git popularity

15. who’s using it

16. Git Concepts

17. .git repo

18. .git repo objects
• a content-addressable file system
• tree
• commit
• blob
• tag

19. .git repo pointers

20. Areas

21. Files
Files are:
Tracked, Untracked or Ignored
.gitignore
Files are in state:
Modified
Staged
Committed

22. Configuration
• name
• email
• git config --global

23. Branches
• diverging
• non-linear development

24. Repositories
• Local (.git directory)
• Remotes (https, ssh)
• On premises
• github.com / bitbucket.org

25. Local Repositories

26. Creating
• .git init
• .git directory creation

27. Cloning
git clone https://github.com/VivaPayments/API.git

28. Making Changes
• the file lifecycle
• staging
• unstaging
• git add filename
• git add *

29. Viewing Status
• current status
• history
• git status
• git log

30. Commiting
• use short descriptive messages
• history
• git commit –m ‘message’

31. Undoing
• amending commits : git commit -amend
• unstage file : git reset HEAD filename
• unmodifying a modified file: git checkout -- filename

32. Branching

33. What is branching
• diverting from the main line
• do some work
• merge back
• have multiple branches at the same time
• switch between branches

34. Default branches
• master
• develop

35. Create new branch
• Have clean working state
• Changes files on your working
directory.
• git branch branchname

36. Switch to branch
• git checkout branchname

37. Merging (no conflicts)

38. Merging (with conflicts)

39. Merging (resolving conflicts)

40. Merging (resolving conflicts)

41. Merging (resolving conflicts)

42. Remote Repositories

43. Remote Repositories
• Viewing
• Adding new remotes
• Fetch / Pull from remotes
• Pushing to remotes
• Pull requests

44. Creating a remote

45. Adding a remote

46. Diffs on remote

47. Pull requests on remote

48. Commits on remote

49. Remote Branches
• origin/{branch}
• pulling
• pushing

50. The git workflow

51. Q&A

52. Resources

53. Resources
• https://git-scm.com/
• https://about.gitlab.com/features/
• http://rogerdudler.github.io/git-guide/
• http://danielkummer.github.io/git-flow-cheatsheet/
• http://stackoverflow.com/questions/tagged/git
• https://github.com/github/gitignore

54. https://gr.linkedin.com/in/chrismylonas
https://www.facebook.com/ChrisMylonas
https://twitter.com/ChrisMylonas

55. Thank you!

56. Lab – Check #presentation channel
feel free to ask anything
master develop aliceFeature
bobFeature
origin/master origin/develop
remote repo
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