Video available at: http://cs50.tv/2011/fall/seminars/Git_magic/Git_magic.mp4

1. Git Magic:
Versioning Files
Like a Boss
Tommy MacWilliam
tmacwilliam@cs50.net

2. Today
• setting up like a boss
• basic git like a boss
• using branches like a boss
• reverting changes like a boss
• collaborating like a boss

3. Git is...
• “Git is distributed version control system
focused on speed, effectivity and real-world
usability on large projects”
• “distributed development”
• “non-linear development”
• “efficient handling of large projects”
• “cryptographic authentication of history”

4. Git is...

5. Git is...
Awesome.

6. Installing Git
• Windows: http://code.google.com/p/
msysgit/
• OS X: http://code.google.com/p/git-osx-
installer/
• Appliance: already installed!

7. Installing Git
root@appliance(~): git
usage: git [--version] [--exec-path[=<path>]] [--html-path]
[-p|--paginate|--no-pager] [--no-replace-objects]
[--bare] [--git-dir=<path>] [--work-tree=<path>]
[-c name=value] [--help]
<command> [<args>]

8. git config --global
user.name
“Tommy MacWilliam”

9. git config --global
user.email
tmacwilliam@cs50.net

11. git init

12. Commits
• snapshots of your project
• what your files look like at a given point
• single event in project history

14. git status

16. git add index.php

19. git add --all

20. git add --all

21. git add --all
git commit

22. Commit Messages
• short message describing what’s different in
this commit
• add any new features?
• fix some bugs?
• break anything?

23. Commit Messages

24. Commit Messages
• http://www.commitlogsfromlastnight.com/

26. git commit -a -m
“oh hi, mark!”

28. git log

29. 5aeebab117b892fa42002146e4c62be676bc4621
b43b0ad1e8108e7ab870d7a54feac93ae8b8600e
461476587780aa9fa5611ea6dc3912c146a91760

30. Commit 5aeebab117b892fa42002146e4c62be676bc4621
ID
b43b0ad1e8108e7ab870d7a54feac93ae8b8600e
461476587780aa9fa5611ea6dc3912c146a91760
HEAD

32. git show

33. git show b43b0

34. git init
git status
git add
git commit
git log
git show

35. git init
git status
git add
git commit
git log
git show

36. Branches
• non-linear development process
• changes on one branch do not affect
other branches
• crazy idea? make a branch
• didn’t work? delete the branch
• all done? merge the branch

38. git branch test

39. git branch test

40. git branch test
git checkout test

41. 5aeeb
b43b0
46147
master

42. 5aeeb
git branch test
b43b0 f862f
46147 36223
master test

44. git merge

45. 5aeeb
b43b0 f862f
46147 36223
git merge
87aed
master test

47. Like a boss.

49. git branch -D test

50. Merge vs. Rebase
• git merge: new commit, non-linear history
• git rebase: no new commit, linear history

51. 5aeeb
git branch test
b43b0 f862f
46147 36223
master test

52. 5aeeb
b43b0
git rebase
46147 f862f 36223
master

53. Conflicts
• change in one branch can be incompatible
with another
• git tries to resolve, but sometimes cannot

54. Conflict Resolution
int main(int argc, char** argv) {
printf(“you invited all my friends”);
}
int main(int argc, char** argv) {
printf(“good thinking!”);
}

55. Conflict Resolution
int main(int argc, char** argv) {
<<<<<<< HEAD:file.c
printf(“you invited all my friends”);
=======
printf(“good thinking!”);
>>>>>>> f862f:file.c
}

56. git checkout
git branch
git merge
git rebase

57. git checkout
git branch
git merge
git rebase

58. git commit -m “oops.”

60. git revert b43b0

61. 5aeeb
b43b0
46147

62. 5aeeb
b43b0
46147
git revert b43b0
42bb4
(b43b0)

63. File-Specific Reverts
• git checkout -- index.php
• replace with version in index
• git checkout b43b0 index.php
• replace with version in commit b43b0

65. git reset --hard b43b0

67. git reflog

69. git bisect

71. Like a boss.

72. git revert
git reset
git checkout
git bisect

73. git revert
git reset
git checkout
git bisect

74. “distributed development”

76. ssh-keygen

78. git push
git@github.com:cs50/project
master

79. git remote add origin
git@github.com:cs50/project

80. git remote add origin
git@github.com:cs50/project
git push origin master

81. git clone
git@github.com:cs50/project

83. git pull origin master

85. git pull --rebase

86. git init
git add --all
git commit
Alice Bob

87. git remote add origin url
git push origin master
Alice Bob

88. git remote add origin url
git push origin master
Alice Bob

89. git clone url
Alice Bob

90. git clone url
Alice Bob

91. git add --all
git commit
Alice Bob

92. git push origin master
Alice Bob

93. git push origin master
Alice Bob

94. git pull origin master
Alice Bob

95. git pull origin master
Alice Bob

97. git branch -a

98. git checkout -b
origin/test

99. scp ~/.ssh/id_rsa.pub
host:~/.ssh/authorized_keys

101. git init --bare

102. git remote add live
user@cloud.cs50.net:~/project

103. git remote add live
user@cloud.cs50.net:~/project
git push live master

104. Hooks
• applypatch-msg • post-applypatch
• commit-msg • pre-commit
• post-commit • pre-commit-msg
• post-receive • pre-rebase
• post-update • update

105. post-receive
#!/bin/sh
GIT_WORK_TREE=/home/tmacwill/public_html
git checkout -f
chmod -R 644 /home/tmacwill/public_html/
*.html
chmod -R 600 /home/tmacwill/public_html/
*.php

107. Like a boss.

108. git clone
git push
git remote
git pull

109. git clone
git push
git remote
git pull

110. More Resources
• http://progit.org/book/
• http://book.git-scm.com/
• http://gitref.org/
• http://git-scm.com/documentation

111. git commit -a -m
“thanks!”