1. Version Control with Git
Version Control with Git

2. Why track/manage revisions?

3. Backup: Undo or refer to old stuff

4. Branch: Maintain old release while working on new

5. Collaborate: Work in parallel with teammates

6. Version Control Systems (VCSs)
Help you track/manage/distribute revisions
Standard in modern development
Examples:
Revision Control System (RCS)
Concurrent Versions System (CVS)
Subversion (SVN)
Git
older
Our focus
newer

7. Distributed VCSs (DVCSs) Git is one!

8. Distributed VCSs (DVCSs) Git is one!
Server has shared copy of repos

9. Distributed VCSs (DVCSs) Git is one!
Clients have working directory + repos copy

10. Distributed VCSs (DVCSs) Git is one!
Clients may share via server or with each other directly

11. GitHub-User Perspective
You
GitHub
Working Dir
Local Repos
Remote Repos

12. Let’s begin with an example…
You
GitHub

13. Configure your Git client (Rails Tutorial 1.3.1)
Install Git
Check config info:
Fix if necessary:
$ git config --list
user.name=Scott Fleming
$ git config --global user.name "John Doe"
$ git config --global user.

14. Log into GitHub and create a repos (with add README option)
You
GitHub
Remote Repos

15. $ git clone https://github.com/sdflem/comp4081_demo.git
You
GitHub
Local Repos
Working Dir
Remote Repos

16. You GitHub Working Dir Local Repos Remote Repos
$ rails new comp4081_demo
You
GitHub
Local Repos
Working Dir
Remote Repos

17. $ cd comp4081_demo $ git add . $ git commit
You
GitHub
Local Repos
Working Dir
Remote Repos

18. File Status Lifecycle git add??? git add git commit git rm???

19. $ git push
You
GitHub
Local Repos
Working Dir
Remote Repos

20. Questions to answer How organized? You GitHub What operations?
Local Repos
Working Dir
Remote Repos
What operations?

21. How the repos is organized

22. How the repos is organized
Commits (from oldest to newest; hashes as commit IDs)

23. How the repos is organized
Snapshot of all files at each commit

24. How the repos is organized
Branch (last commit)

25. How commit works
Before

26. How commit works
After

27. Common Workflow Create temp local branch Checkout temp branch
Edit/Add/Commit on temp branch
Checkout master branch
Pull to update master branch
Merge temp branch with updated master
Delete temp branch
Push to update server repos
Make changes in local branch
Merge with GitHub repos

28. Organization with two branches

29. Organization with two branches
Last commit of each branch

30. Organization with two branches
Currently checked out branch

31. Common Workflow Create temp local branch Checkout temp branch
Edit/Add/Commit on temp branch
Checkout master branch
Pull to update master branch
Merge temp branch with updated master
Delete temp branch
Push to update server repos

32. How git branch works
$ git branch testing
Before

33. How git branch works
$ git branch testing
After

34. Common Workflow Create temp local branch Checkout temp branch
Edit/Add/Commit on temp branch
Checkout master branch
Pull to update master branch
Merge temp branch with updated master
Delete temp branch
Push to update server repos

35. How git checkout works
$ git checkout testing
Before

36. How git checkout works
$ git checkout testing
After

37. Common Workflow Create temp local branch Checkout temp branch
Edit/Add/Commit on temp branch
Checkout master branch
Pull to update master branch
Merge temp branch with updated master
Delete temp branch
Push to update server repos

38. How git commit works with multiple branches
Edit some stuff
$ git commit -a
Before

39. How git commit works with multiple branches
Edit some stuff
$ git commit -a
After

40. Common Workflow Create temp local branch Checkout temp branch
Edit/Add/Commit on temp branch
Checkout master branch
Pull to update master branch
Merge temp branch with updated master
Delete temp branch
Push to update server repos

41. How git checkout works
$ git checkout master
Before

42. How git checkout works
$ git checkout master
After

43. Common Workflow Create temp local branch Checkout temp branch
Edit/Add/Commit on temp branch
Checkout master branch
Pull to update master branch
Merge temp branch with updated master
Delete temp branch
Push to update server repos

44. How git pull works
Someone else pushed
$ git pull
Before

45. How git pull works
Someone else pushed
$ git pull
After

46. Common Workflow Create temp local branch Checkout temp branch
Edit/Add/Commit on temp branch
Checkout master branch
Pull to update master branch
Merge temp branch with updated master
Delete temp branch
Push to update server repos

47. How git merge works
$ git merge testing
Before

48. How git merge works
$ git merge testing
e2b92
After

49. Common Workflow Create temp local branch Checkout temp branch
Edit/Add/Commit on temp branch
Checkout master branch
Pull to update master branch
Merge temp branch with updated master
Delete temp branch
Push to update server repos

50. How to delete branches
$ git branch -d testing
e2b92
Before

51. How to delete branches
$ git branch -d testing
e2b92
After

52. Common Workflow Create temp local branch Checkout temp branch
Edit/Add/Commit on temp branch
Checkout master branch
Pull to update master branch
Merge temp branch with updated master
Delete temp branch
Push to update server repos

53. How git push works Should update server repos $ git push
e2b92
Should update server repos
(if no one else has pushed commits to master branch since last pull)

54. Tips git output contains lots of hints
git status is your friend!
Merging may not be as easy as I showed
E.g.: Multiple collabs updated same parts of file
See Pro Git 3.2
Pull before starting temp branch
Team communication important!

55. Pair Activity Share one GitHub repos Practice parallel editing/merging
two different files (FOO.txt/BAR.txt)
different parts (top/bottom) of same file (FOO.txt)
same line of same file (FOO.txt)