Migrating from SVN to Git, I've prepared a deck for training my team on Git concepts.

1. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
HPLiveNetworkMeetGit
Liran Tal
2013
Goodbye merge hell, conflicts, and awfully slow svn operations

2. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
Motivation
“Already know you that which you need” - Yoda

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Motivation
Decentralized
• Faster, really.
• Complete repository clone.
• Developers can work “offline”, committing all their work locally and pushing to a ‘primary’ repository later.
• Redundant and enterprise-ready, if required.
Lightweight Branches
• Cheap and quick
• Used often, and merged often.

4. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.4
Motivation
Drives for better development methodology
• Gitflow – A successful git branching model
• Code reviews
Extra curriculum points for reading 
− http://nvie.com/posts/a-successful-git-branching-model

5. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
Roadmap
“Always in motion, the future is” - Yoda

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Roadmap
Plans for implementing Git in HP Live Network.
Using Git,
better, all of us
• Gradually
migrating the
rest of the R&D
teams to Git
Using Git,
better
• Working with
Gitflow
development
methodology
Using Git
• Preliminary
evaluation of Git
• Understanding
Git – knowledge
gap
• Migrating
backend SVN
repository to Git
• Using Git in a
single team (3
developers) as
case study
Git kick-off
• Motivation for
Git
• Roadmap

7. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
GitOverview
“Try not. Do or do not, there is no try” - Yoda
(heavily based on Git Pro book, @see git-scm.com/book)

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Git Overview
CVCS
SVN operations mostly need to consult a remote
server repository
DVCS
Git operations mostly run on the local
repository (and later pushed to a remote
server)

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Git Overview
Changes
SVN-like data model
Gnapshots
Git maintains a snapshot of the data

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Git Overview
The Three States
• Modified
• Staged (the staging area is also known as the index)
• Committed

11. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.11
Git Overview
Git For Work
• IntelliJ
− In our experience Eclipse with EGIT support is awful
• PHPStorm – bundled with Git integration
• Command line Git, my preferred option
Other Git Tools
• TortoiseGit
• Gitk

12. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
GitBasics
“Try not. Do or do not, there is no try” - Yoda

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Initializing a git repository
Git Basics
Starting fresh
• git init
Working from an existing repository
• git clone <repository-url>
− we know this as ‘svn checkout <repository-url>’

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Adding work
Git Basics
Commiting your work
• git add <file>
− git add -p <file>
− git add -I <file>
• git status
• git commit [file] -m <commit-message>

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Common commands
Git Basics
Commiting your work
• git status
• git branch
• git diff
− --staged – see changes between staged to last commit
• git rm
• git mv
• .gitignore
• git log
− -p – view diff
− --stat – view a summary of commit file stats
− --pretty=oneline --pretty=full or --pretty=format:”%h - %an, %ar : %s”
− --graph
− --since=2.weeks

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Undoing
Git Basics
Undoing changes
• git commit –amend
− Commits the staging area again instead of the previous commit
• git reset HEAD <file>
− Unstage a previously staged file
• git checkout -- <file>
− Revert local changes to that file

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Remotes
Git Basics
Working with Remotes
• git remote -v
− Lists remotes configured for this repository
• git remote add <shortname> <url>
− Adding a remote
• git fetch <remote> <branch>
− Fetch the changes from the remote repository (not yet merging them)
• git pull <remote> <branch>
− Fetch and merge changes from the remote repository to the local branch

18. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.18
Remotes
Git Basics
Working with Remotes
• git push <remote> <branch>
− Push your changes to the remote repository
− Pushing is only successful if your local copy is up to date with the remote
• git remote show <remote>
− Inspecting the remote for information
• git remote rename <remote> <new-remote>
− Renaming a remote
• git remote rm <remote>
− Removing a remote

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Tagging
Git Basics
Lightweight and Annotated Tags
• git tag -a v2.0 -m “portal release 2.0” [hash]
− Annotated tags (notice the -a flag) are saved as full Git objects meaning they contain author information,
email, checksum, etc.
• git tag v2.0
− Lightweight tags are just pointers to a commit (don’t provide -a, -m or -s)
• git push <remote> --tags
− Pushing our tags to the remote repository as they don’t get pushed with a plain ‘git push’

20. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.
GitBranches
“Try not. Do or do not, there is no try” - Yoda

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Git Branches
Overview
• Diverge from the main line of development and continue to do work without messing with that main line
• Expensive process, often requiring you to create a new copy of your source code directory
Git killer branching
• Incredibly lightweight and prompt

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Git Branches
Overview
• Stream-line a development methodology

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Git Branches
Starting off
• Starting on a fresh ‘master’ branch with 3 files:
− README
− License
− test.rb
• After performing git add && git commit, an example visual
representation is as such:

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Git Branches
Starting off
• With each commit in time a new commit object is created and objects are pointing to parents (zero or more)

25. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.25
Git Branches
Starting off
• The ‘master’ branch is simply a pointer that moves forward with each commit you make

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Git Branches
Branching off
• Creating new branches means creating new pointers to a certain commit
• git branch testing

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Git Branches
Branching off
• HEAD pointer is used to point to the local branch you’re working on now
• We’re still on ‘master’ cause we only created a new branch (testing) but didn’t yet
switch to it

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Git Branches
Branching off
• HEAD pointer is used to point to the local branch you’re working on now
• We’re still on ‘master’ cause we only created a new branch (testing) but didn’t yet
switch to it
• git checkout testing

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Git Branches
Branching off
• HEAD and testing branch pointers are both updated with each new commit
• git commit -a -m “new file”

30. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.30
Git Branches
Branching off
• Going back to our original ‘master’ branch:
− Updated the HEAD pointer
− Working directory looks different now, representing the state of the ‘master’ branch
• git checkout master

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Git Branches
Diverged road
• Commiting work on the master branch again will diverge and enable us to work on 2 paths
• git commit -a -m “another commit”

32. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.32
Git Branches
Re-cap
• Branches are simply pointers
• Due to commits data structure it is easy enough to find proper merge base and that process is mostly done
automatic for us

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WebPresenceforGit

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Gitblit
Gitblit
• Open source Java project for hosting Git repositories
• Includes a web interface for managing and interacting with repositories (attempts to live up to the Github
promise)

35. © Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.35
Gitblit
Gitblit
• Open source Java project for hosting Git repositories
• Includes a web interface for managing and interacting with repositories (attempts to live up to the Github
promise)
• Includes a Java UI to manage users and their
certificates
• Feature-full, including repository federation
and other cool stuff

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Gitblit
User Setup
• Configure your git:
− git config --global http.sslverify false
− git config --global http.sslkey /pathto/lirantal.key
− git config --global http.sslcert /pathto/lirantal.pem
− git config --global http.proxy ""
− git config --global user.name "Liran Tal"
− git config --global user.email "liran.tal@hp.com"
• You’re ready to clone:
git clone https://gitserver:8443/git/hpln.git