Git Introduction

Mike Ward

MikeWard.tel

My Comments

• aiming for the middle 80%
• how it works
• live demo
• supporting tools & services

What Is Source Control Management?

save snapshots of your project

Why Version Control?

Why VCS?

• accidents can be fixed
• collaborate: people can work on same files
• never again need to see index.php~
• be professional

You don't need to be an expert!

• only use need a dozen commands to start
• never need to know internals
• branching/merging is easy!

VCS Types

Centralized Systems

• one authoritative server
• one complete repository
• working copies

Distributed Systems

• no authoritative repository
• work offline
• lots of choices about workflows
• encourages collaboration

Delta based storage

Delta based storage

Delta based storage

Delta based storage

Delta based storage

DAG based storage

DAG based storage

DAG based storage

DAG based storage

DAG based storage

DAG based storage

Directed Acyclic Graph storage

Directed Acyclic Graph storage

Directed Acyclic Graph storage

Directed Acyclic Graph storage

Concept: Three Buckets

Git Started

Git Started

Git Started: Installation

• can download source: git.or.cz
• http://code.google.com/p/msysgit - installer.exe
• port install git-core +svn (or brew install)
• yum install git-core
• apt-get install git-core
• rpm install git-core

Git Setup

git config --global user.name "mike ward"

git config --global user.email "mike@mikeward.net"

cat ~/.gitconfig

Basic Commands

• about 150 commands
• most used internally, by other commands
• about half used by humans
• try to gradually learn some

Git Started: git init

git init - creates a new repository

.git directory

• config file
• hooks
• index
• object database
• references

cat ~/.gitconfig

Git Started: git status

• which files are not tracked
• which tracked files have changed
• which files are staged

Git Started: git add

Git Started: add interactive

• individually choose which tracked files to stage
• choose which untracked files to stage
• stage "hunks" of files

Git Started: commit

Git Started: commit

• create new commit object
• pointer to content that was staged
• pointer to parent(s)
• commit metadata

Git Started: commit (options)

• commit -am "message" (auto add all)
• commit --amend (revise msg for last commit current branch)
• commit -p (commit hunks)

Git Commands: git branch & git checkout

demo - basic commands

Git Commands: git branch & git checkout

git branches

Git Commands: git branch

• each branch points to a commit

Git Commands: git branch

• each branch points to a commit
• create branch: git branch dev

Git Commands: HEAD

• each branch points to a commit
• create branch: git branch dev
• HEAD points to current branch

Git Commands: git checkout

• git checkout moves HEAD pointer
• very different from svn switch

Git Commands: git checkout

Git Commands: git checkout

Git Commands: git checkout

git checkout -b dev

git branch dev && git checkout dev

Git Commands: git merge & git rebase

merging and rebasing

Git Commands: git merge

Git Commands: git merge

Git Commands: git merge

Git Commands: git rebase

• allows you to write history differently
• rebase -i
• "cleaner" history

Git Commands: git rebase

Git Commands: git rebase

Git Commands: git rebase vs git merge

Git Commands: git rebase -i

Git Commands: git rebase -i

Git Commands: git rebase -i

Git Commands: git rebase -i

Git Commands: git rebase -i

Git Commands: git rebase -i

Git Commands: git rebase -i

Git Tips: working on branches

• create branch
• checkout branch (can do both together)
• make changes, save file
• diff or view in browser to see changes
• add, commit on that branch
• merge, rebase or discard

Git Commands: git tag

• git tag (list current tags)
• lightweight vs annotated tags
• git tag -a v1.0 -m "tag message"
• git show v1.0
• git tag -a v1.0 84f70c2
• git tag -s and git tag -v

Git Commands: git remote

git remote

Git Commands: git remote

git remote add #{nickname} #{url}

Git Commands: git remote

git remote add #{nickname} #{url}

Git Commands: git remote

git remote add #{nickname} #{url}

Git Commands: git remote

git remote

Git Commands: git remote

git remote -v

Git Commands: git remote

git remote show #{nickname}

Git Commands: git remote

git remote rename #{from} #{to}

git remote rm #{remote-name}

Git Commands: git remote

things to do with remotes

Git Started: git clone

• create local empty git repo
• fetch existing repository
• merge
• note: "svn checkout" is different

git clone revisited

Git Commands: git push

git push

Git Commands: git push

git push #{destination} #{branch}

Git Commands: git push

git push #{destination} #{branch}

Git Commands: git push

git push #{destination} #{branch}

Git Commands: git log

git log

Git Commands: git log

git log -3

Git Commands: git log

git log -3

Git Commands: git log

git log -3

Git Commands: git log

git log -3

Git Commands: git log

git log -3

Git Commands: git log

git log -3

Git Commands: git log

git log -p

Git Commands: git log

git log --since=yesterday

Git Commands: git log

git log --pretty=oneline

Git Commands: git log

git log --oneline --graph --decorate --all

Git Commands: git log

git log --oneline --graph --decorate --all

Git Basics: .gitignore

• text file listing what to ignore
• config info, large binaries, logfiles
• sitewide, but can be overridden per dir
• .project
• *.swp
• tmp/**/*

Git Commands: git fetch

• fetch all info from remote that is not in your local repo
• this does NOT automatically merge
• afterwards you have refs to all remote branches

Git Commands: git pull

git pull = git fetch + git merge

Git Commands: git stash

• you have changes that are NOT ready to commit
• but you need to do something else
• stash your changes
• come back and apply those changes later

Git Commands: git ls-files

• list staged/unstaged/deleted/unmerged files
• matching patterns
• per directory basis
• using info from index
• ls-remote

.git directory

• config file
• hooks
• index
• object database
• references

cat ~/.gitconfig

git hooks

• run scripts before and after commands
• pre: spell check, jslint, run autotests
• post: notifications, kick off build scripts
• can be local or remote!
• commit, rebase, fetch, pull, push, etc.

git local hooks

• pre-commit: error checking
• post-commit: notifications
• pre- and post-rebase
• post-checkout
• post-merge

git remote hooks

• pre-receive: validation before accepting push
• post-receive: notifications, triggering build scripts, etc.
• update: same as pre-receive but run once per branch
• tip: use client hooks to warn users about server hooks gotchas

.git directory

• config file
• hooks
• index
• object database
• references

Git internals: objects

Git internals: objects

Git internals: objects

Git internals: objects

Git internals: objects

Git internals: objects

Git internals: objects

Git internals: objects

Git internals: objects

Git Commands: git show

used to show objects (blobs, trees, tags and commits)

Git Commands: undoing changes

I screwed up a file

git checkout -- filename

Git Commands: undoing changes

I screwed up many files

git checkout -f branchname

Git Commands: undoing changes

I screwed up the whole branch

git branch -d branchname

Git Commands: undoing changes

revert the last commit

git revert HEAD

Git Commands: git gc

Git Commands: git diff

Git Tips: git add -i

• choose modified files to stage
• choose untracked files to stage
• choose chunks of code to stage

Git Tips: git add -p

• stage "hunks" of files
• for each hunk, choices include y, n, a, d, e (edit)
• s - split it up into smaller pieces!

Git Utilities

git utilities

Git Utilities

git-svn

gitk

git instaweb

git instaweb

Git Tips: git GUIs

• tortoise git/windows, Git Cola
• tower/Mac - beauty
• smartgit - Mac, Windows, Linux
• plugins for eclipse, others

Collaboration in Git

Collaboration in Git

Collaboration in Git

Collaboration in Git

Collaboration in Git

Collaboration in Git

Collaboration in Git

Collaboration in Git

Git Tips: protocols

• file://
• ssh://
• http(s)://
• git://
• rsync://

Git Commands Revisited

deploying with git

deploying with git

deploying with git

deploying with git

deploying with git

deploying with git

• supported by capistrano, fabric
• heroku
• others?

hosted repos for Git

• Github
• unfuddle, gitorious, beanstalk, bitbucket, many more
• roll your own

resources

• https://github.com/mdw/git_preso - these slides
• git-scm.org
• http://blip.tv/scott-chacon/
• http://ProGit.org/book
• #git , #github
• gitref.org

The End

Thanks!