Basic introduction to git, the object database and the most common commands.

1. Introduction Basics Using git Other final
Git - the stupid content tracker
Henrik Austad
UNINETT Sigma A/S
15. Oct 2009

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about:henrik
Henrik Austad
MSc Engineering Cybernetics
UNINETT Sigma A/S & NDGF
System Developer

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Background - In the beginning ... was patch
• Initially written by Linus Torvalds to replace BitKeeper
• First “working” version: April 18th 2005
• git v1.0 December 21th 2005
• Written for
• Speed
• Track changes
• Large projects with active history

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Contenders
• Bazaar (bzr)
• Darcs
• Mercurial (hg)
• svk

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What does “distributed” mean?
• Everything is local.

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What does “distributed” mean?
• Everything is local.
• No “need” for a centralized repository.

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What does “distributed” mean?
• Everything is local.
• No “need” for a centralized repository.
• Disk is cheap - network is not.

8. Introduction Basics Using git Other final
What does “distributed” mean?
• Everything is local.
• No “need” for a centralized repository.
• Disk is cheap - network is not.
• Lower threshold for new developers, you don’t need special
access to the repository to get started.

9. Introduction Basics Using git Other final
git objects
• type
• blob
• tree
• commit
• tag
• size
• content

10. Introduction Basics Using git Other final
git objects
• type
• blob
• tree
• commit
• tag
• size
• content
Figure: git example.credits: Scott Chacon

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Normal commands
• git clone repo dest
• git init

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Normal commands
• git status
• git log start..end
• git branch name of new branch start commit
• git checkout branchname

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Normal commands
• git add path/to/file
• git commit -s -m “short commit msg”
• git rebase -i commit
• git cherry-pick commit

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Normal commands
• git remote
• git push
• git pull
• git fetch

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Normal commands
• git tag
• git diff
• git format-patch
• git am

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Normal commands
• git config –global user.name “Henrik Austad”
• git config –global user.email “henrik@austad.us”
• git config user.email “local@project.mail”
• git config push.default current

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git merge vs. git rebase
An example, 3 branches, commits done in alphabetical order

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git merge vs. git rebase
Merge F and D giving H, then H and G giving I

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git merge vs. git rebase
Rebase F onto D, rewriting F to F’, then C-F’ onto G

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Hooks - it’s a kind of magic
See .git/hooks/
• pre-commit
• post-update

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Visualization
• git log –graph
• git-gui
• gitk
• qgit

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Questions?
http://git-scm.com/
mailto:git@vger.kernel.org
http://www.kernel.org/pub/software/scm/git/docs/
everyday.html