Git Presentation - Handout
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This document summarizes Christopher Giroir's presentation on Git for beginners. It covers Git internals like objects, branches and tags. It then discusses Git usage including creating and committing changes, inspecting the repository, distributing changes, merging and rebasing branches. The presentation concludes with additional topics like working with remotes, configuration and tips.
![Internals Usage Distribution Merging and Rebasing Extras
Git for mere mortals
https://github.com/Kelsin/git-presentation
Christopher Giroir
July 26th, 2011
Christopher Giroir Git for mere mortals
Internals Usage Distribution Merging and Rebasing Extras
1 Internals
Objects
Branches and Tags
2 Usage
Creating and Commiting
Inspection
3 Distribution
Advantages
Architecture
Command Examples
4 Merging and Rebasing
Merging
Rebase
5 Extras
Remotes
Misc
Christopher Giroir Git for mere mortals
Internals Usage Distribution Merging and Rebasing Extras
Objects
Object Store
The git object store is a big black box and we like it that way.
It was written for speed and correctness
Comparisons
More information than CVS
More sane than SVN
More efficient than Mercurial
Christopher Giroir Git for mere mortals
Internals Usage Distribution Merging and Rebasing Extras
Objects
Blobs
_^]XYZ[Blob
Blobs store file data (text or binary).
Labeled by SHA1. If the content changes, so does the SHA.
Christopher Giroir Git for mere mortals](https://image.slidesharecdn.com/git-presentation-handout-130506104541-phpapp01/85/Git-Presentation-Handout-1-320.jpg)
![Internals Usage Distribution Merging and Rebasing Extras
Objects
Trees
_^]XYZ[Blob
_^]XYZ[Tree //
??
_^]XYZ[Blob
Trees point to blobs
Represent the entire state of the working directory
Also labeled by SHA’s.
Christopher Giroir Git for mere mortals
Internals Usage Distribution Merging and Rebasing Extras
Objects
Commits
onmlhijkCommit _^]XYZ[Blob
onmlhijkCommit
OO
//_^]XYZ[Tree
CC§§§§§§§§§§§§§
//_^]XYZ[Blob
Points to a tree object and parent commit(s)
Stores author and date information
Labeled by SHA’s.
Christopher Giroir Git for mere mortals
Internals Usage Distribution Merging and Rebasing Extras
Objects
Important Distinction!
Commits link to entires TREES not DIFFS.
Diffs are not stored in git, they are computed.
Christopher Giroir Git for mere mortals
Internals Usage Distribution Merging and Rebasing Extras
Branches and Tags
Pointers
Most other things in git are pointers to commits.
?>=<89:;a //
v3.0.1
?>=<89:;b //
bbbbbbbbb
Master
?=89:;c //?=89:;d //?=89:;e
SAVE-465
?=89:;g //
origin/SAVE-576
?=89:;h //?=89:;i
SAVE-576
Branches are just labels to commit SHA’s
Tags are just labels with meta information
Christopher Giroir Git for mere mortals](https://image.slidesharecdn.com/git-presentation-handout-130506104541-phpapp01/85/Git-Presentation-Handout-2-320.jpg)
Git Presentation - Handout
- 1. Internals Usage Distribution Merging and Rebasing Extras Git for mere mortals https://github.com/Kelsin/git-presentation Christopher Giroir July 26th, 2011 Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras 1 Internals Objects Branches and Tags 2 Usage Creating and Commiting Inspection 3 Distribution Advantages Architecture Command Examples 4 Merging and Rebasing Merging Rebase 5 Extras Remotes Misc Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Objects Object Store The git object store is a big black box and we like it that way. It was written for speed and correctness Comparisons More information than CVS More sane than SVN More efficient than Mercurial Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Objects Blobs _^]XYZ[Blob Blobs store file data (text or binary). Labeled by SHA1. If the content changes, so does the SHA. Christopher Giroir Git for mere mortals
- 2. Internals Usage Distribution Merging and Rebasing Extras Objects Trees _^]XYZ[Blob _^]XYZ[Tree // ?? _^]XYZ[Blob Trees point to blobs Represent the entire state of the working directory Also labeled by SHA’s. Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Objects Commits onmlhijkCommit _^]XYZ[Blob onmlhijkCommit OO //_^]XYZ[Tree CC§§§§§§§§§§§§§ //_^]XYZ[Blob Points to a tree object and parent commit(s) Stores author and date information Labeled by SHA’s. Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Objects Important Distinction! Commits link to entires TREES not DIFFS. Diffs are not stored in git, they are computed. Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Branches and Tags Pointers Most other things in git are pointers to commits. ?>=<89:;a // v3.0.1 ?>=<89:;b // bbbbbbbbb Master ?=89:;c //?=89:;d //?=89:;e SAVE-465 ?=89:;g // origin/SAVE-576 ?=89:;h //?=89:;i SAVE-576 Branches are just labels to commit SHA’s Tags are just labels with meta information Christopher Giroir Git for mere mortals
- 3. Internals Usage Distribution Merging and Rebasing Extras Branches and Tags Rewriting History Rewriting a commit changes it’s SHA Any commit after it changes as well Most branch operations are quick and painless Can shoot yourself in the foot and heal it back up again Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Creating and Commiting Starting Out Setting User Info git config --global user.name Christopher Giroir git config --global user.email kelsin@valefor.com Completely New Repo cd dir-with-code git init Cloning any accessible repo git clone git@github.com:Kelsin/configs.git cd configs Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Creating and Commiting Commits Initial Commit git add . git commit -m Initial Commit Editing some files git add edited-file.rb git commit -m Improved everything Adding to previous commit git add edited-file.rb git commit --amend Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Inspection Status and Diffs Normal Status git status What’s current changed? git diff Changes from only one file git diff example-file.rb Changes between branches git diff master Christopher Giroir Git for mere mortals
- 4. Internals Usage Distribution Merging and Rebasing Extras Inspection Show and Log Show current commit git show Show some other commit git show 234ab32 Show log of recent commits git log Show pretty log git log --graph --decorate --oneline Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Inspection Refs and Objects By commit id git show 234ab32 By branch git show master By tag git show v3.0.2 Relative git show HEAD^ Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Advantages Distributed Source Control Only difference from remote and local (normally): working directories Can function offline Can “push” and “pull” from each other, as well as servers Each of our computers serves as a backup of the server Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Architecture Location Descriptions Git has 4 locations where commits are stored Remote Repo Any remote object store Local Repo You local object store Index A single spot to “stage” commits Working Directory These are the files you are editing Christopher Giroir Git for mere mortals
- 5. Internals Usage Distribution Merging and Rebasing Extras Command Examples Locations and Commands Working git add Index git commit Local Repo git push ## git checkout gg Remote Repo git fetch cc BC@A git pull OO Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Merging Fast Forward Merging git checkout master git merge SAVE-234 ?=89:;a //?=89:;b //?=89:;c //?=89:;d //?=89:;e Master SAVE-234 Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Merging Merging git checkout master git merge SAVE-234 ?=89:;a //?=89:;b // aaaaaaaaa ?=89:;c //?=89:;d //?=89:;e //?=89:;76540123j Master ?=89:;g //?=89:;h //?=89:;i @@¢¢¢¢¢¢¢¢¢ SAVE-234 Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Merging No Fast Forward Merging git checkout master git merge --no-ff SAVE-234 ?=89:;a //?=89:;b bbbbbbbbb //?=89:;76540123f Master ?=89:;c //?=89:;d //?=89:;e @@ SAVE-234 Christopher Giroir Git for mere mortals
- 6. Internals Usage Distribution Merging and Rebasing Extras Rebase Rebase git checkout SAVE-234 git rebase master ?=89:;a //?=89:;b //?=89:;c //?=89:;d //?=89:;e wwooooooooooooooooo Master GFED@ABC?=89:;g //GFED@ABC?=89:;h //ONMLHIJKGFED@ABCi SAVE-234 Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Remotes Remote Commands Adding remote git remote add origin git@github.com:Kelsin/configs.git Fetch all remote objects git fetch Show all branches git branch -a Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Remotes Pushing Push objects from source to destination git push origin source:destination Removing remote branch git push origin :destination Setting upstream git push -u origin SAVE-453 Force pushes git push -f origin SAVE-453 Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Remotes Pulling Pull in remote changes git pull origin master Special case Executes: git fetch git merge Merges in to your current branch Christopher Giroir Git for mere mortals
- 7. Internals Usage Distribution Merging and Rebasing Extras Misc Git Config File My git config is available at https://github.com/Kelsin/configs/blob/master/.gitconfig Push defaults Commiter name and email Color settings Aliases Christopher Giroir Git for mere mortals Internals Usage Distribution Merging and Rebasing Extras Misc Some Tips Always work on branches When in doubt use GitX or gitk to see what you are doing When in doubt save a new branch so you can always get back Add the current git branch into your prompt Explore with rebase and cleaning up code before final push Christopher Giroir Git for mere mortals