Git allows creating snapshots of project files called commits. Users can create branches to develop features independently and then merge them together. Common commands include commit to save snapshots, checkout to switch branches, merge to combine work, and push/pull to share commits between remote repositories. Advanced techniques involve rebasing to clean up commit histories and resolving merge conflicts when branches diverge.

1. Git Playground
Shinho

2. Contents
Key concepts
Basic level
Advanced level
Additional tips that you don’t want (need) to use(know) YET

3. Git
Centralized Version Control
Distributed Version Control

4. Git commands

5. Key concept: Snapshots
Git keeps "snapshots" of the entire state of the project.

6. Key concept: Repository
Between repositories
● Clone
● Push
● Fetch, Pull
Within a repository
● Commit
● Merge
● ...other actions

7. Basic: Within a Repo

8. Key concept: Commit
Act of creating a snapshot.

9. Key concept: Branch
git checkout -b branch_name
git branch branch_name

10. Key concept: HEAD
● Symbolic name for the currently checked out commit.
● Detaching HEAD from branch is possible.

11. Key concept: HEAD
● symbolic name for the currently checked out commit
git checkout C4
git checkout bugFix

12. Branch: Merge
git merge bugFix

13. Branch: Merge
git checkout bugFix
git merge master

14. Branch: Rebase
git rebase master

15. Branch: Rebase
git rebase bugFix

16. Basic: Between Repos

17. Key concept: Clone
Git clone remote_server_repository_url

18. Key concept: Fetch

19. Key concept: Pull = Fetch + Merge

20. Key concept: Pull
cloned 2 commits on remote master
1 commit on local master Git pull

21. Key concept: Push

22. Advanced:
Working Together

23. Pull Request

24. Failed Push
git pull
git push
git fetch
git rebase o/master
git push
Or
git pull --rebase
git push
git push >>> fails!!

25. Cherry-pick
git cherry-pick C2 C4

26. Merge conflict

27. Merge conflict

28. Advanced:
Nice and neat history

29. Stash
DEMO
Use git stash when you want to record the current state of the
working directory and the index, but want to go back to a clean
working directory.
Personally, I don’t use stash that much, instead of this I commit
current changes temporarily and rebase or reset later.

30. Reset & Revert
git reset HEAD~1
git revert HEAD

31. Interactive rebase (change the commits order)
git rebase -i HEAD~4
pick

32. Some problematic cases
● You have committed a change (or changes) to a branch, but the commit(s)
should be in another branch.
○ The branch history is only in LOCAL
○ The branch history is already pushed to REMOTE
● You want to split up current branch state into two or three different branches.
○ The branch history is only in LOCAL
○ The branch history is already pushed to REMOTE

33. Additional tips that you
don’t want (need) to
use(know) YET

34. Clean up merged branches on your local repo
git branch --merged | egrep -v "(^*|master|dev)" | xargs git branch -d

35. Rewriting histories (squash & rebase)
https://confluence.atlassian.com/bitbucketserver/pull-request-merge-strategies-844499235.html

36. Fork and Pull Request

37. References
https://www.slideshare.net/HubSpot/git-101-git-and-github-for-beginners
https://courses.cs.washington.edu/courses/cse403/13au/lectures/git.ppt.pdf
https://learngitbranching.js.org/
https://blog.carbonfive.com/2017/08/28/always-squash-and-rebase-your-git-commi
ts/
https://git-scm.com/book/en/v2/Git-Tools-Rewriting-History

38. Cheat sheet
If you want to use alias for git, install zsh and set plugin for git.
e.g. ‘ga’ instead of ‘git add’, ‘gp’ for ‘git push’...,
● Install ZSH: https://github.com/robbyrussell/oh-my-zsh/wiki/Installing-ZSH
● Install Oh-My-ZSH: sh -c "$(curl -fsSL
https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/inst
all.sh)"
● Set plugin: https://github.com/robbyrussell/oh-my-zsh#plugins
If you want to add additional alias for yourself.
● vi ~/.zshrc
● Put this on any line (usually the last line)
○ alias some_shorten_command=”some full command”
○ E.g. alias gitr="git branch --merged | egrep -v "(^*|master|dev)" | xargs git branch -d"
■ Then you can use `gitr` on your terminal.

39. Cheat sheet
Description Command using alias Full command
Add changed files to staging ga . git add .
Commit staged files with message gc -m 'some message' git commit -m 'some message'
Add changed files to staging and commit with
message. but newly created files are not affected
gc -a -m 'some message' git commit -a -m 'some message'
Create branch gco -b 'branch name' git checkout -b 'branch name'
Change branch gco 'branch name' git checkout 'branch name'
Reset last 2 commits, but keeping the changes N/A git reset --soft HEAD~2
Pull the latest changes of a branch gco 'branch name'
gl
gco 'branch name'
git pull
Push the commits to remote server gp git push
Change to master branch gcm git checkout master
Merge master branch of remote server to current
branch
gmom git merge origin/master
Clean up already merged branches gcm
gitr **
** if you added alias of this command by the
instruction on slide 38, you can use the short
command.
git checkout master
git branch --merged | egrep -v "(^*|master|dev)" |
xargs git branch -d