~/ git --help

Talk given at the following conferences/events:
- Android Makers (April / 2023)

Have you ever had an issue with git? Don't know which git command to use? Is your git slow in a big mono repo project?

If you answered YES to any of these questions, this talk is for you. First we will learn how git works under the hood which will give us a better understanding of several git commands. Second we will dive into the git features on Android Studio. Last but not least, share some tips on how to make the most out of git.

After this talk, you will have the right knowledge to master git. Once you start to understand it, the terminology will make more sense and youll eventually learn to love it!

Transcript

1. ~/ git --help Zhenlei Ji @zhenleiji
2. 🗓 Agenda 1. A brief history of GIT 2. What is GIT? 3. GIT under the hood 4. Learn commands through examples 5. Android Studio + GIT 6. Configuration for your Monorepo 7. Final considerations
3. 👩🏫 A brief history of GIT
4. Linus Torvalds
5. Why did he give it this name?
7. Linus Torvalds “the stupid content tracker”
8. Linus Torvalds 😀 “global information tracker”
9. Linus Torvalds 🤬 “goddamn idiotic truckload of sh*t”
10. 🤔 What is GIT?
11. https://github.com/git/git “Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.”
12. https://github.com/git/git “Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.”
13. distributed control system
14. unusually rich command set add am archive bisect branch bundle checkout cherry-picky citool clean clone commit describe diff fetch format-patch gc gitk grep gui init log maintenance merge mv notes pull push range-diff rebase restore revert rm shortlog show sparse-checkout stash status submodule switch tag worktree
15. unusually rich command set add am archive bisect branch bundle checkout cherry-picky citool clean clone commit describe diff fetch format-patch gc gitk grep gui init log maintenance merge mv notes pull push range-diff rebase restore revert rm shortlog show sparse-checkout stash status submodule switch tag worktree and more…
16. 🦸 😵💫
17. 🤓 GIT under the hood
18. Git model SHA1 (Secure Hash Algorithm) 6 ff 87c4664981e4397625791c8ea3bbb5f2279a3
19. Git model SHA1 (Secure Hash Algorithm) 6 ff 87c4664981e4397625791c8ea3bbb5f2279a3
20. Git model SHA1 (Secure Hash Algorithm) 6 ff 87c4664981e4397625791c8ea3bbb5f2279a3
21. Internal Git model Tree aabbcc1 (SHA1) +aabbccf: blob = fi le.txt +ddee ff 1: blob = other.txt +aabbcc2: tree = folder Tree aabbcc2 (SHA1) + ff feee1: blob = nested.txt +dddee22: blob = other.txt Blob aabbccf (SHA1) +content = fi le.txt Blob ddee ff 1 (SHA1) +content = other.txt Blob ff feee1 (SHA1) +content = folder/nested.txt Blob dddee22 (SHA1) +content = folder/other.txt Commit abc123f (SHA1) +tree = aabbcc1 (SHA1) +author = Zhenlei +commiter = Zhenlei +parent = aaabbb5 +comment = A single commit Tag 7755 ff e (SHA1) +object = abc123f (SHA1) +type = commit +tagger = Zhenlei +comment = My tag comment
22. Git model .git/objects
23. https://learngitbranching.js.org/
24. Me “GIT is a graph structure of file systems with a bunch of commands to modify the graph.” In a nutshell
25. 👨🏫 Learn commands through examples
26. 1. Upload a new project to a remote repository
27. Create new project
28. Set default branch ~/ git con fi g --global init.defaultBranch main
29. Create git repository ~/ git init https://githooks.com/ 👈
30. Edit .gitignore
31. Edit .gitignore https://www.toptal.com/developers/gitignore
32. Edit .gitignore https://www.toptal.com/developers/gitignore
33. Add new or changed files to the staging area ~/ git add <pathspec>
34. Displays the state of the working directory and the staging area ~/ git status
35. Displays the state of the working directory and the staging area ~/ git status
36. Record the changes in the repository ~/ git commit
37. Open VIM 1. :wq 2. :x 3. shift+zz ❤ How to exit?
38. Set a default editor ~/ git con fi g --global core.editor <editor>
39. Create a connection to other repositories ~/ git remote add <name> <url>
40. Create a connection to other repositories ~/ git remote add <name> <url> Github Repo (origin) Sophia’s Repo (sophia) Your Repo
41. Upload local repository to a remote repository ~/ git push -u origin <branch>
42. Upload local repository to a remote repository ~/ git push -u origin <branch>
43. 2. Create a new feature
44. Local Branches Remote Branches origin/featureA Sequence of commands C1 C3 main featureA* origin/main C2 C1 C3 C2 Remote Repository (github) HEAD Working on featureA
45. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main featureA* origin/main C2 C1 C3 C2 Remote Repository (github) HEAD ~/ git checkout main
46. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main* featureA origin/main C2 C1 C3 C2 HEAD ~/ git checkout main Remote Repository (github)
47. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main* featureA origin/main C2 C1 C3 C2 C4 HEAD C4 ~/ git pull Remote Repository (github) git fetch git merge origin/main
48. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main* featureA origin/main C2 C1 C3 C2 C4 HEAD C4 ~/ git pull Remote Repository (github) git fetch git merge origin/main
49. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main featureA origin/main C2 C1 C3 C2 C4 HEAD C4 ~/ git checkout -b featureB featureB*
50. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main featureA origin/main C2 C1 C3 C2 C4 HEAD C4 ~/ git commit -m “C5” featureB* C5
51. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main featureA origin/main C2 C1 C3 C2 C4 HEAD C4 Update branch with the changes in main featureB* C5 1. git checkout main
52. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main* featureA origin/main C2 C1 C3 C2 C4 HEAD C4 Update branch with the changes in main featureB C5 1. git checkout main 2. git pull
53. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main* featureA origin/main C2 C1 C3 C2 C4 HEAD C4 Update branch with the changes in main featureB C5 1. git checkout main 2. git pull Remote Repository (github) git fetch git merge origin/main C6 C6
54. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main* featureA origin/main C2 C1 C3 C2 C4 HEAD C4 Update branch with the changes in main featureB C5 C6 C6 1. git checkout main 2. git pull 3. git checkout -
55. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main featureA origin/main C2 C1 C3 C2 C4 C4 Update branch with the changes in main featureB* C5 C6 C6 1. git checkout main 2. git pull 3. git checkout - HEAD
56. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main featureA origin/main C2 C1 C3 C2 C4 C4 Update branch with the changes in main featureB* C5 C6 C6 1. git checkout main 2. git pull 3. git checkout - 4. git merge main C7 HEAD
57. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main featureA origin/main C2 C1 C3 C2 C4 C4 Update branch with the changes in main featureB* C5 C6 C6 1. git checkout main 2. git pull 3. git checkout - 4. git merge main C7 HEAD
58. Me “Do I really need local branch main?”
59. 🙅
60. Me “Why not use an origin/main branch?” 🤯
61. Local Branches Local Remote Branches origin/featureA Sequence of commands C1 C3 main featureA* origin/main C2 C1 C3 C2 Remote Repository (github) HEAD Working on featureA git branch -D main
62. Local Branches Local Remote Branches origin/featureA Sequence of commands featureA* origin/main C2 C1 C3 C2 Remote Repository (github) HEAD ~/ git fetch C4 git fetch
63. Local Branches Local Remote Branches origin/featureA Sequence of commands featureA* origin/main C2 C1 C3 C2 HEAD ~/ git checkout -b featureB origin/main C4 featureB
64. Local Branches Local Remote Branches origin/featureA Sequence of commands featureA origin/main C2 C1 C3 C2 ~/ git checkout -b featureB origin/main C4 featureB* HEAD
65. Local Branches Local Remote Branches origin/featureA Sequence of commands featureA origin/main C2 C1 C3 C2 ~/ git commit -m “C5” featureB* C5 HEAD C4
66. Local Branches Local Remote Branches origin/featureA Sequence of commands featureA origin/main C2 C1 C3 C2 Update branch with the changes in main featureB* C5 HEAD C4 C6 Remote Repository (github) git fetch 1. git fetch
67. Local Branches Local Remote Branches origin/featureA Sequence of commands featureA origin/main C2 C1 C3 C2 Update branch with the changes in main featureB* C5 HEAD C4 C6 1. git fetch 2. git rebase origin/main
68. Local Branches Local Remote Branches origin/featureA Sequence of commands featureA origin/main C2 C1 C3 C2 Update branch with the changes in main featureB* C5 C4 C6 1. git fetch 2. git rebase origin/main C5’ HEAD
69. Many people “ What is the difference between merge and rebase?”
70. Merge
71. Merge ~/ git merge <commit id | branch> featureA C1 featureB* C3 C2 HEAD
72. Merge ~/ git merge featureA featureA C1 featureB* C2 C3 HEAD
73. Merge ~/ git merge featureA featureA C1 featureB* C2 C3 HEAD C4 What is the parent of C4? 🤔 C2? C3? Both?
74. https://twitter.com/HenryHo ff man/status/1442820054643625987 Merge
75. Merge
76. Merge
77. Rebase
78. Rebase ~/ git rebase <commit id|branch> featureA C1 featureB* C3 C2 HEAD C4
79. Rebase ~/ git rebase featureA featureA C1 featureB* C3 C2 HEAD C4
80. Rebase ~/ git rebase featureA featureA C1 featureB* C3 C2 HEAD C4 C3’
81. Rebase ~/ git rebase featureA featureA C1 featureB* C3 C2 HEAD C4 C3’ C4’
82. https://itnext.io/git-force-vs-force-with-lease-9d0e753e8c41
83. Rebase Interactive ~/ git rebase -i <commitId | branch> featureA C1 C2 C3 C4 C5 HEAD
84. Rebase Interactive ~/ git rebase -i HEAD~4 featureA C1 C2 C3 C4 C5 HEAD
85. Rebase Interactive ~/ git rebase -i C2 featureA C1 C2 C3 C4 C5 HEAD
86. Rebase Interactive ~/ git rebase -i C2 featureA C1 C2 C3 C4 C5 HEAD
87. Rebase Interactive ~/ git rebase -i C2 featureA C1 C2 C3 C4 C5 HEAD
88. Rebase Interactive ~/ git rebase -i C2 featureA C1 C2 C3 C4 C5 HEAD
89. Rebase Interactive ~/ git rebase -i C2 featureA C1 C2 C3 C4 C5 C2’ HEAD
90. Rebase Interactive ~/ git rebase -i C2 featureA C1 C2 C3 C4 C5 C6 HEAD
91. C3’ Rebase Interactive ~/ git rebase -i C2 featureA C1 C2 C3 C4 C5 C6 HEAD
92. C34 Rebase Interactive ~/ git rebase -i C2 featureA C1 C2 C3 C4 C5 C6 HEAD
93. C34 Rebase Interactive ~/ git rebase -i C2 featureA C1 C2 C3 C4 C5 C6 HEAD C5’
95. 3. When was the bug introduced?
98. ~/ git bisect Use binary search to fi nd the commit that introduced a bug 1. git bisect start 2. git bisect bad 3. git bisect good 4. git bisect skip 5. git bisect reset https://git-scm.com/docs/git-bisect
100. ~/ git bisect run validate.sh 1. 0 (zero) if the commit is good 2. 125 if the commit can’t be tested (skip) 3. Anything else (often 127) if the commit is bad https://git-scm.com/docs/git-bisect 😎
101. 4. Houston, we have a problem!
103. Restore the project’s history ~/ git re fl og
104. Restore the project’s history ~/ git reset --hard 2a88570fa7c https://www.atlassian.com/git/tutorials/rewriting-history/git-re fl og
105. 🫶 Android Studio + GIT
106. Commit cmd+k
107. Push cmd+shift+k
108. Git tab cmd+9
109. Git tab cmd+9
112. 👆
113. 👆
114. GIT blame 👆
115. GIT conflicts
116. GIT conflicts
117. Pro tip Create shortcut for fetch and branches cmd+shift+a
118. Pro tip Create shortcut for fetch and branches opt+enter Fetch: opt+f Branches: opt+g
119. Pro tip Run fetch <opt+f>
120. Pro tip Show branches <opt+g>
121. Plugin Well integrated with Github
122. Plugin Well integrated with Github
123. iTerm + Oh My Zsh Add git plugin https://medium.com/ayuth/iterm2-zsh-oh-my-zsh-the-most-power-full-of-terminal-on-macos-bdb2823fb04c
124. iTerm + Oh My Zsh Add git plugin
125. https://www.youtube.com/watch?v=XMUnUotuvGw
126. 🪨 Configuration for your monorepo
127. Github configuration
128. Github configuration
129. Enable auto-prune Delete the refs to branches that don't exist on the remote 1. git con fi g --global fetch.prune true 2. git con fi g remote.origin.prune true 1.73s -> 0.02s
130. Enable FSMonitor GIT fi le system monitor https://github.blog/2022-06-29-improve-git-monorepo-performance-with-a- fi le-system-monitor/ Git version 2.37.0
131. Enable FSMonitor GIT fi le system monitor https://github.blog/2022-06-29-improve-git-monorepo-performance-with-a- fi le-system-monitor/ Git version 2.37.0
132. Enable FSMonitor GIT fi le system monitor https://github.blog/2022-06-29-improve-git-monorepo-performance-with-a- fi le-system-monitor/ Git version 2.37.0
133. Enable FSMonitor GIT fi le system monitor https://github.blog/2022-06-29-improve-git-monorepo-performance-with-a- fi le-system-monitor/ Git version 2.37.0
134. Enable FSMonitor GIT fi le system monitor https://github.blog/2022-06-29-improve-git-monorepo-performance-with-a- fi le-system-monitor/ Git version 2.37.0 1.73s -> 0.02s
135. 🙌 Final considerations
136. There are more git commands to explore
137. Many ways to do the same thing
138. Many resources
139. https://learngitbranching.js.org/
141. https://git-scm.com/book/en/v2
142. Aristotle “The more you know, the more you know you don’t know.”
143. Thanks
144. @zhenleiji Zhenlei Ji
145. References • https://learngitbranching.js.org/ • https://book.git-scm.com/book/en/v2 • https://github.com/git/git • https://medium.com/gitopia/git-a-stupid-content-tracker-d0ef5b86865f • https://www.simplilearn.com/git-rebase-vs-merge-article • https://delicious-insights.com/en/posts/git-bisect/ • https://www.atlassian.com/git/tutorials/rewriting-history/git-re fl og • https://github.blog/2015-06-08-how-to-undo-almost-anything-with-git/ • https://github.blog/2022-06-29-improve-git-monorepo-performance-with-a- fi le-system- monitor/