Describe how git works internally using small and perfect plumbing commands. The slide have been used at GDG DevFest 2014 and SOSCON 2014. The slide can be updated later. And, the latest version would always be provided from this page always.

1. How GIT Works Internally
SeongJae Park <sj38.park@gmail.com>

2. Nice To Meet You
SeongJae Park
sj38.park@gmail.com

3. Git
DVCS(Distributed Version Control System)
http://git-scm.com/images/logos/downloads/Git-Logo-2Color.png

4. Git
DVCS(Distributed Version Control System)
Made-by Linus Torvalds For Linux
http://git-scm.com/images/logos/downloads/Git-Logo-2Color.png
http://cdn.memegenerator.net/instances/400x/37078331.jpg

5. Git
Many Projects Use Git Because It’s Awesome
http://blog.appliedis.com/wp-content/uploads/2013/11/android1.png
http://upload.wikimedia.org/wikipedia/en/4/40/Octocat,_a_Mascot_of_Github.jpg
http://upload.wikimedia.org/wikipedia/commons/thumb/3/35/Tux.svg/512px-Tux.svg.png
http://git-scm.com/images/logos/downloads/Git-Logo-2Color.png

6. Git
Hard To Learn
Confusing For CVCS Users
Push? Pull? Fetch? Rebase? HEAD???
http://www.quickmeme.com/img/fd/fd09e17b3393b2ea1cd7e52af1ad7c77f3c2d7a83e9f47d4b90ba3af52dde329.jpg
http://git-scm.com/images/logos/downloads/Git-Logo-2Color.png

7. Git: The Information Manager From Hell
http://www.youblob.com/sites/default/files/styles/large/public/field/image/frontlego1.png?itok=XA5CXt84

8. Git: The Information Manager From Hell
$ git log e83c516
commit e83c5163316f89bfbde7d9ab23ca2e25604af290
Author: Linus Torvalds <torvalds@ppc970.osdl.org>
Date: Thu Apr 7 15:13:13 2005 -0700
Initial revision of "git", the information manager from hell
http://www.youblob.com/sites/default/files/styles/large/public/field/image/frontlego1.png?itok=XA5CXt84

9. Git: The Information Manager From Hell
That’s Why So Confusing And Hard To Learn
$ git log e83c516
commit e83c5163316f89bfbde7d9ab23ca2e25604af290
Author: Linus Torvalds <torvalds@ppc970.osdl.org>
Date: Thu Apr 7 15:13:13 2005 -0700
Initial revision of "git", the information manager from hell
http://www.youblob.com/sites/default/files/styles/large/public/field/image/frontlego1.png?itok=XA5CXt84

10. This Time, We Will...
See How Git Works From The Scratch
https://lh4.googleusercontent.com/gBpfuABUjSNi2RagtJrGi8TW-pmtgak_0qtGOGubihvKH-5-umreO9C
wJgjX2kaA9E7RkLwtEwiDnoMtOgm4iMJ0IWhvXlzlKL1kNVUYWuNa-gLRtRoyNjkVYg

11. This Time, We Will...
See How Git Works From The Scratch
Just For Fun
...Or To Be Friend Of Git
https://lh4.googleusercontent.com/gBpfuABUjSNi2RagtJrGi8TW-pmtgak_0qtGOGubihvKH-5-umreO9C
wJgjX2kaA9E7RkLwtEwiDnoMtOgm4iMJ0IWhvXlzlKL1kNVUYWuNa-gLRtRoyNjkVYg

12. This Time, We Will...
See How Git Works From The Scratch
Just For Fun
...Or To Be Friend Of Git
Forget About The
Complicated Commands
This Time
https://lh4.googleusercontent.com/gBpfuABUjSNi2RagtJrGi8TW-pmtgak_0qtGOGubihvKH-5-umreO9C
wJgjX2kaA9E7RkLwtEwiDnoMtOgm4iMJ0IWhvXlzlKL1kNVUYWuNa-gLRtRoyNjkVYg

13. In Short,
Git Is A Content-Addressable Storage System
http://www.juliagiff.com/wp-content/uploads/2014/03/tld
r_trollcat.jpg

14. In Short,
Git Is A Content-Addressable Storage System
Blob, Tree, Commit, Reference. That’s It =3
http://www.juliagiff.com/wp-content/uploads/2014/03/tld
r_trollcat.jpg

15. Plumbers: Unsung Heroes Behind
● Git Looks Graceful Owing To Plumbing
Commands Consisting Them
http://cfile4.uf.tistory.com/image/182FF7244CFDDFB33CC999
http://cfile29.uf.tistory.com/image/18574F224CFDD89B163073

16. Plumbers: Unsung Heroes Behind
● Git Looks Graceful Owing To Plumbing
Commands Consisting Them
○ The Wounded Foots Are What We Interested In
http://cfile4.uf.tistory.com/image/182FF7244CFDDFB33CC999
http://cfile29.uf.tistory.com/image/18574F224CFDD89B163073

17. Again, From The Scratch
VCS? Why? How?

18. Why VCS?
Usual Life Of File
FileA ver 0 FileB ver 0

19. Why VCS?
Usual Life Of File
FileA ver 0 FileB ver 1FileB ver 0

20. Why VCS?
Usual Life Of File
FileA ver 0 FileB ver 1

21. Why VCS?
Usual Life Of File
FileB ver 1 FileA ver 1FileA ver 0

22. Why VCS?
Usual Life Of File
FileB ver 1 FileA ver 1

23. Why VCS?
Usual Life Of File
FileB ver 2FileA ver 1FileB ver 1

24. Why VCS?
Usual Life Of File
FileB ver 2FileA ver 1

25. Why VCS?
Usual Life Of File
FileB ver 2FileA ver 1

26. We Need Version Control System
VCS Would...
Record Every Changes Safely, Efficiently

27. We Need Version Control System
VCS Would...
Record Every Changes Safely, Efficiently
Able To Check Out Any Version

28. We Need Version Control System
VCS Would...
Record Every Changes Safely, Efficiently
Able To Check Out Any Version
Easy To Read History

29. Brute-force Idea
Version Control Using File System

30. Brute-force Idea
Rename / Backup Every Files Whenever
Change Made

31. Brute-force Idea
Rename / Backup Every Files Whenever
Change Made
$ ls
foo.c

32. Brute-force Idea
Rename / Backup Every Files Whenever
Change Made
$ ls
foo.c
foo_20140111.c

33. Brute-force Idea
Rename / Backup Every Files Whenever
Change Made
$ ls
foo.c
foo_20140111.c
foo_final.c

34. Brute-force Idea
Rename / Backup Every Files Whenever
Change Made
$ ls
foo.c
foo_20140111.c
foo_final.c
foo_realfinal.c
foo_planb.c
foo_finalfinal.c

35. Brute-force Idea
Rename / Backup Every Files Whenever
Change Made
$ ls
foo.c
foo_20140111.c
foo_final.c
foo_realfinal.c
foo_planb.c
foo_finalfinal.c

36. Brute-force Idea + History Isolation
Keep Working / History Directory Seperately.

37. Brute-force Idea + History Isolation
Keep Working / History Directory Seperately.
Better, But...
$ find . -type f
./working/foo.c
./history/foo_20140111.c
./history/foo_final.c
./history/foo_realfinal.c
./history/foo_planb.c
./history/foo_finalfinal.c

38. TODOs From Version Control Using FS
Use Storage Space-Efficiently

39. TODOs From Version Control Using FS
Use Storage Space-Efficiently
Easy History Searching

40. Mission #1:
Store History Space-Efficiently

41. Basic Idea: Avoid Duplicated Objects

42. Basic Idea: Avoid Duplicated Objects
Content-Addressable Storage System

43. Basic Idea: Avoid Duplicated Objects
Content-Addressable Storage System
Key: SHA-1 Hash Of Object’s Content
Value: Compressed Content

44. Basic Idea: Avoid Duplicated Objects
Content-Addressable Storage System
Key: SHA-1 Hash Of Object’s Content
Value: Compressed Content
Same Content Never Saved Twice

45. Save / Load ‘homer’
$ mkdir simpsons; cd simpsons; git init
Initialized empty Git repository in simpsons/.git/
$ echo ‘homer’ | git hash-object -w --stdin
4aa0bfa07f1680c50a1567ecc37bc3b6aa567b8f
$

46. Save / Load ‘homer’
$ mkdir simpsons; cd simpsons; git init
Initialized empty Git repository in simpsons/.git/
$ echo ‘homer’ | git hash-object -w --stdin
4aa0bfa07f1680c50a1567ecc37bc3b6aa567b8f
$ find .git/objects/ -type f
.git/objects/4a/a0bfa07f1680c50a1567ecc37bc3b6aa567b8f
$

47. Save / Load ‘homer’
$ mkdir simpsons; cd simpsons; git init
Initialized empty Git repository in simpsons/.git/
$ echo ‘homer’ | git hash-object -w --stdin
4aa0bfa07f1680c50a1567ecc37bc3b6aa567b8f
$ find .git/objects/ -type f
.git/objects/4a/a0bfa07f1680c50a1567ecc37bc3b6aa567b8f
$ git cat-file -p 4aa0b
homer
$ git cat-file -t 4aa0b
blob

48. What `hash-object -w` did
hash_object_w(‘homern’)

49. What `hash-object -w` did
hash_object_w(‘homern’)
# Save compressed header + content at sha1 path
def hash_object_w(content):
header = ‘blob %d0’ % len(content)
store = header + content
sha1 = sha.new(store).hexdigest()

50. What `hash-object -w` did
hash_object_w(‘homern’)
# Save compressed header + content at sha1 path
def hash_object_w(content):
header = ‘blob %d0’ % len(content)
store = header + content
sha1 = sha.new(store).hexdigest()
dir = ‘.git/objects/’ + sha1[0:2] + ‘/’
filename = sha1[2:]

51. What `hash-object -w` did
hash_object_w(‘homern’)
# Save compressed header + content at sha1 path
def hash_object_w(content):
header = ‘blob %d0’ % len(content)
store = header + content
sha1 = sha.new(store).hexdigest()
dir = ‘.git/objects/’ + sha1[0:2] + ‘/’
filename = sha1[2:]
open(dir + filename, ‘w’).write(
zlib.compress(store))

52. Version Control Using Hash Value
$ echo “bart” > son
$ git hash-object -w son
e00ddae83bdab443f4267426623aa34636c935f2
$

53. Version Control Using Hash Value
$ echo “bart” > son
$ git hash-object -w son
e00ddae83bdab443f4267426623aa34636c935f2
$ echo “hugo” > son
$ git hash-object -w son
8e1e2f09585e021c9727585af72e10871d7be7ce
$

54. Version Control Using Hash Value
$ echo “bart” > son
$ git hash-object -w son
e00ddae83bdab443f4267426623aa34636c935f2
$ echo “hugo” > son
$ git hash-object -w son
8e1e2f09585e021c9727585af72e10871d7be7ce
$
# Need former version, “bart”
$ git cat-file -p e00dd > son
$ cat son
bart

55. TODOs From Version Control Using FS
Use Storage Space-Efficiently
Easy History Searching

56. Version Control Using Hash Value
● DONE
○ Efficient Space Usage
○ Safe Record / Checkout Of History
https://www.sciencenews.org/sites/default/files/main/articles/sad_opener.jpg

57. Version Control Using Hash Value
● DONE
○ Efficient Space Usage
○ Safe Record / Checkout Of History
● TODO
○ Support Directory Structure
○ History Management
○ Better Reference Than Hash Value
https://www.sciencenews.org/sites/default/files/main/articles/sad_opener.jpg

58. WAIT!
Q: What If Small Changes Inside A Big File?

59. WAIT!
Q: What If Small Changes Inside A Big File?
$ du -h bigfile.c
188Kbigfile.c
$ du -sh
408K.
$ echo ‘/* small change */’ >> bigfile.c
$ git commit -as -m “small change, big difference”
$ du -sh
496K.
$

60. WAIT!
Q: What If Small Change Inside A Big File?
A: Git Pick up Diff-Only If Necessary
But, Don’t Forget To Keep It Small, Simple
$ du -sh
496K.
$ git gc
Counting objects: 6, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (4/4), done.
Writing objects: 100% (6/6), done.
Total 6 (delta 1), reused 0 (delta 0)
$ du -sh
388K.

61. Mission #2:
Store History Of Directories

62. tree Object
Point Other Objects(Using Hash) With Name

63. tree Object
Point Other Objects(Using Hash) With Name
tree
blob blob tree
blob
a113f2
mommy b8934
son
c9240
pets
d9b13
cat

64. tree Object
Point Other Objects(Using Hash) With Name
“A Root tree Object Is A Snapshot”
tree
blob blob tree
blob
a113f2
mommy b8934
son
c9240
pets
d9b13
cat
I’m a
snapshot

65. tree object
$ mkdir pets; echo ‘snowball’ > pets/cat
$ git update-index --add son pets/cat
$ git write-tree
15ee76ed3e744b6796950d07f26283d033ea3ea7
$

66. tree object
$ mkdir pets; echo ‘snowball’ > pets/cat
$ git update-index --add son pets/cat
$ git write-tree
15ee76ed3e744b6796950d07f26283d033ea3ea7
$ git cat-file -p 15ee7
040000 tree 85ab72cf1946dc56392718a1aafb3c6f66c02072 pets
100644 blob 8e1e2f09585e021c9727585af72e10871d7be7ce son
$

67. tree object
$ mkdir pets; echo ‘snowball’ > pets/cat
$ git update-index --add son pets/cat
$ git write-tree
15ee76ed3e744b6796950d07f26283d033ea3ea7
$ git cat-file -p 15ee7
040000 tree 85ab72cf1946dc56392718a1aafb3c6f66c02072 pets
100644 blob 8e1e2f09585e021c9727585af72e10871d7be7ce son
$ git cat-file -p 85ab7
100644 blob 6a1f952e1baedcb3db93a3ea5e3389e5a87941e9 cat
$ git cat-file -p 6a1f9
snowball
$

68. Internal Data Structure
tree
blob tree
8e1e2
son
85ab7
pets

69. Internal Data Structure
tree
blob tree
blob
6a1f9
cat
8e1e2
son
85ab7
pets

70. Version Control Using tree Object
$ echo “bart” > son
$ git update-index --add son
$ git write-tree
661e6ad514a7f05c46c2931280cb78a339d34ee2
$

71. Version Control Using tree Object
$ echo “bart” > son
$ git update-index --add son
$ git write-tree
661e6ad514a7f05c46c2931280cb78a339d34ee2
$ git cat-file -p 661e6
040000 tree 85ab72cf1946dc56392718a1aafb3c6f66c02072 pets
100644 blob e00ddae83bdab443f4267426623aa34636c935f2 son
$

72. Version Control Using tree Object
$ echo “bart” > son
$ git update-index --add son
$ git write-tree
661e6ad514a7f05c46c2931280cb78a339d34ee2
$ git cat-file -p 661e6
040000 tree 85ab72cf1946dc56392718a1aafb3c6f66c02072 pets
100644 blob e00ddae83bdab443f4267426623aa34636c935f2 son
$ git cat-file -p e00dd
bart
$

73. Internal Data Structure
tree
blob tree
blob
8e1e2
son
85ab7
pets
6a1f9
cat

74. Internal Data Structure
tree
blob tree
blob
tree
blob
e00dd
son85ab7
pets
8e1e2
son
85ab7
pets
6a1f9
cat

75. Version Control Using Hash Value
● DONE
○ Efficient Space Usage
○ Safe Record / Checkout Of History
● TODO
○ Support Directory Structure
○ History Management
○ Better Reference Than Hash Value
https://www.sciencenews.org/sites/default/files/main/articles/sad_opener.jpg

76. Version Control Using tree Object
● DONE
○ Efficient Space Usage
○ Safe Record / Checkout Of History
○ Support Directory Structure
● TODO
○ History Management
○ Better Reference Than Hash Value
https://www.sciencenews.org/sites/default/files/main/articles/sad_opener.jpg

77. Mission #3:
Commit Message

78. commit Object
Describe Who / When / Why The Change Made
http://modthink.com/wp-content/uploads/2013/05/WhoWhatWhenWhereWHY.jpg

79. commit Object
Describe Who / When / Why The Change Made
Point A tree Object With Information Above
http://modthink.com/wp-content/uploads/2013/05/WhoWhatWhenWhereWHY.jpg

80. commit Object
$ echo '1st commit' | git commit-tree 661e6
0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0
$

81. commit Object
$ echo '1st commit' | git commit-tree 661e6
0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0
$
$ git cat-file -p d075c
tree 661e6ad514a7f05c46c2931280cb78a339d34ee2
author SeongJae Park <s**@gmail.com> 1410527921 +0900
committer SeongJae Park <s**@gmail.com> 1410527921 +0900
1st commit
$

82. commit Object
$ echo '1st commit' | git commit-tree 661e6
0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0
$
$ git cat-file -p d075c
tree 661e6ad514a7f05c46c2931280cb78a339d34ee2
author SeongJae Park <s**@gmail.com> 1410527921 +0900
committer SeongJae Park <s**@gmail.com> 1410527921 +0900
1st commit
$
Who When
Why

83. Version Control Using commit Object
$ echo '2nd commit' | git commit-tree 15ee7 -p 0ca73
003b5e66caa89a6228c7b4d91e0475e56bf1bdf6
$
$ git cat-file -p 003b5
tree 15ee76ed3e744b6796950d07f26283d033ea3ea7
parent 0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0
author SeongJae Park <s**@gmail.com> 1410528231 +0900
committer SeongJae Park <s**@gmail.com> 1410528231 +0900
2nd commit
$

84. Internal Data Structure
That’s Why People Says, “A Commit is a
snapshot”
tree
blob tree
blob
tree
blob
commit commit
tree
parent
tree
85ab7
pets
8e1e2
son
85ab7
pets
6a1f9
cat
e00dd
son

85. Version Control Using tree Object
● DONE
○ Efficient Space Usage
○ Safe Record / Checkout Of History
○ Support Directory Structure
● TODO
○ History Management
○ Better Reference Than Hash Value
https://www.sciencenews.org/sites/default/files/main/articles/sad_opener.jpg

86. Version Control Using commit Object
● DONE
○ Efficient Space Usage
○ Safe Record / Checkout Of History
○ Support Directory Structure
○ Manage History Well
● TODO
○ Better Reference Than Hash Value
https://www.sciencenews.org/sites/default/files/main/articles/sad_opener.jpg

87. Mission #4:
Human Readable Name

88. Git References
File With Human-Readable Name

89. Git References
File With Human-Readable Name
Storing SHA-1 Value Of commit Object

90. Git References
File With Human-Readable Name
Storing SHA-1 Value Of commit Object
Resides In .git/refs/

91. Git References Using echo
$ echo "0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0" > .git/refs/heads/first
$

92. Git References Using echo
$ echo "0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0" > .git/refs/heads/first
$
$ git log --pretty=oneline first
0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0 1st commit
$

93. Git References Using echo
$ echo "0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0" > .git/refs/heads/first
$
$ git log --pretty=oneline first
0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0 1st commit
$
$ find .git/refs/heads -type f
.git/refs/heads/first
.git/refs/heads/master
$

94. Git References Using update-ref
$ git update-ref refs/heads/master 003b5
$ git log --pretty=oneline master
003b5e66caa89a6228c7b4d91e0475e56bf1bdf6 2nd commit
0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0 1st commit
$

95. Git References Using update-ref
$ git update-ref refs/heads/master 003b5
$ git log --pretty=oneline master
003b5e66caa89a6228c7b4d91e0475e56bf1bdf6 2nd commit
0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0 1st commit
$
$ find .git/refs/heads -type f
.git/refs/heads/first
.git/refs/heads/master
$

96. Git References Using update-ref
$ git update-ref refs/heads/master 003b5
$ git log --pretty=oneline master
003b5e66caa89a6228c7b4d91e0475e56bf1bdf6 2nd commit
0ca7304ad6f5a40f8a26ba05b10b514ff2d8d8a0 1st commit
$
$ find .git/refs/heads -type f
.git/refs/heads/first
.git/refs/heads/master
$
$ cat .git/refs/heads/master
003b5e66caa89a6228c7b4d91e0475e56bf1bdf6

97. Internal Data Structure
tree
blob tree
blob
tree
blob
commit commit
tree
parent
tree
85ab7
pets
8e1e2
son
85ab7
pets
e00dd
son
6a1f9
cat

98. Internal Data Structure
tree
blob tree
blob
tree
blob
commit commit
tree
parent
tree
refs/heads/
master
refs/heads/
first
85ab7
pets
8e1e2
son
85ab7
pets
e00dd
son
6a1f9
cat

99. Version Control Using commit Object
● DONE
○ Efficient Space Usage
○ Safe Record / Checkout Of History
○ Support Directory Structure
○ Manage History Well
● TODO
○ Better Reference Than Hash Value
https://www.sciencenews.org/sites/default/files/main/articles/sad_opener.jpg

100. Version Control Using Reference
● DONE
○ Efficient Space Usage
○ Safe Record / Checkout Of History
○ Support Directory Structure
○ Manage History Well
○ Easy To Remember Specific Snapshot
● TODO
○ ...cooperation?
https://www.sciencenews.org/sites/default/files/main/articles/sad_opener.jpg

101. FAQ #1
How Git Make-up Working Directory?

102. How Git Knows Current Commit?
Answer: HEAD

103. How Git Knows Current Commit?
Answer: HEAD
HEAD Points reference Using ref format(Not
SHA-1)

104. How Git Knows Current Commit?
Answer: HEAD
HEAD Points reference Using ref format
(Not SHA-1)
$ cat .git/HEAD
ref: refs/heads/master

105. HEAD
$ cat .git/HEAD
ref: refs/heads/master
$

106. HEAD
$ cat .git/HEAD
ref: refs/heads/master
$ git branch
first
* master
$

107. HEAD
$ cat .git/HEAD
ref: refs/heads/master
$ git branch
first
* master
$
$ git symbolic-ref HEAD refs/heads/first
$ cat .git/HEAD
ref: refs/heads/first
$ git branch
* first
master

108. Internal Data Structure
tree
blob tree
blob
tree
blob
commit commit
tree
parent
tree
refs/heads/
master
refs/heads/
first
85ab7
pets
8e1e2
son
85ab7
pets
e00dd
son
6a1f9
cat

109. Internal Data Structure
tree
blob tree
blob
tree
blob
commit commit
tree
parent
tree
refs/heads/
master
refs/heads/
first
.git/HEAD
85ab7
pets
8e1e2
son
85ab7
pets
e00dd
son
6a1f9
cat

110. FAQ #2
Cloned. Now Fetch Or Pull ?

111. Fetch / Pull
Fetch Or Pull To Get Latest Code?

112. Fetch
● Just Fetch Remote Repository’s Objects And
References To Local Git Internal Storage

113. Fetch
● Just Fetch Remote Repository’s Objects And
References To Local Git Internal Storage
● If You Need The Changes On Your Working
Directory,

114. Fetch
● Just Fetch Remote Repository’s Objects And
References To Local Git Internal Storage
● If You Need The Changes On Your Working
Directory,
○ Manually Merge Them Using git-merge Or,
○ Checkout

115. Fetch
Refspec Describes Source / Destination
$ cat .git/config | grep remote -A3
[remote "origin"]
url = git://10.0.0.1/git/simpsons.git
fetch = +refs/heads/*:refs/remotes/origin/*
Source Destination

116. Fetch: Before
url = git://10.0.0.1/git/simpsons.git
fetch = +refs/heads/*:refs/remotes/origin/*
tree
blob tree
blob
a134f
son
799cf
pets
7cc07
cat
tree
blob
65464
son
799cf
pets
commit commit
tree
parent
tree
refs/
heads/
master
.git/
HEAD
git://10.0.0.1/git/simpsons.git
tree
blob tree
blob
a134f
son
799cf
pets
7cc07
cat
commit
tree
refs/
heads/
master
.git/
HEAD
file:///home/sjpark/simpsons

117. Fetch: After
url = git://10.0.0.1/git/simpsons.git
fetch = +refs/heads/*:refs/remotes/origin/*
tree
blob tree
blob
a134f
son
799cf
pets
7cc07
cat
tree
blob
65464
son
799cf
pets
commit commit
tree
parent
tree
refs/
heads/
master
.git/
HEAD
git://10.0.0.1/git/simpsons.git
tree
blob tree
blob
a134f
son
799cf
pets
7cc07
cat
tree
blob
65464
son
799cf
pets
commit commit
tree
parent
tree
refs/
remotes/
origin/
master
refs/
heads/
master
.git/
HEAD
file:///home/sjpark/simpsons

118. git merge origin/master
tree
blob tree
blob
a134f
son
799cf
pets
7cc07
cat
tree
blob
65464
son
799cf
pets
commit commit
tree
parent
tree
refs/
remotes/
origin/
master
refs/
heads/
first
.git/
HEAD
tree
blob tree
blob
a134f
son
799cf
pets
7cc07
cat
tree
blob
65464
son
799cf
pets
commit commit
tree
parent
tree
refs/
remotes/
origin/
master
refs/
heads/
first
.git/
HEAD

119. Pull
Pull Is Just An Abbrev Of Fetch && Merge
May Merge Conflict Occur…
Pull Is Sufficient For Simple Project

120. Wrap-up

121. In Short,
Git Is A Content-Addressable File System
Blob, Tree, Commit, Reference. That’s It =3
http://www.juliagiff.com/wp-content/uploads/2014/03/tld
r_trollcat.jpg

122. Thank you :)
http://jeancharpentier.files.wordpress.com/2012/02/capture-plein-c3a9cran-01022012-230955.jpg

123. Slide-share
http://www.slideshare.net/SeongJaePark1/dee
p-darkside-ofgit
Latest Version Of This Slide Would Be
There

124. References
http://git-scm.com/book
http://www.youtube.com/watch?v=4XpnKHJAok8
http://en.wikipedia.org/wiki/The_Simpsons

125. This slide has been used for
Samsung Open Source CONference 2014

126. This work by SeongJae Park is licensed under the
Creative Commons Attribution-ShareAlike 3.0 Unported
License. To view a copy of this license, visit
http://creativecommons.org/licenses/by-sa/3.0/.