Introduction to: &

Max Claus Nunesmaxcnunes@gmail.comhttp://blog.maxcnunes.nethttps://github.com/maxcnunes

Version Control Systems

• Without• Local• Centralized• Distributed

What?!

Without Version Control Systems

• Copy files into another directory• Store or Share files backups by email• Store or Share files by pendrive

Local Version Control Systems

• Just a local Database

• Systems:– RCS - Revision

Control System (Today is centralized)

http://git-scm.com

Centralized Version Control Systems

• A Central Server

• The most used for the companies

• Systems:– CVS– Subversion– TFS

http://git-scm.com

Centralized Version Control Systems

Advantages• Everyone knows to a certain degree what everyone else on

the project is doing• Administrators have more control over what everyone can

do

Disadvantages• If Server goes down, this means nobody can save changes• If HD Server breaks, this means good bye all control version

history

Distributed Version Control Systems

• Distributed: each client has fully mirror of the repository

• Systems:– Git –Mercurial– Bazaar

http://git-scm.com

Distributed Version Control Systems

Advantages• Everytime someone pulls from the central repository, Git gets a

full history of the changes• Most of the functionalities doesn’t need access to some

network. So we can work even not connected to the internet• A project can be associated to a more than one remote

repository• You can do anything just using the console

Disadvantages• Git requires some learning curve to understand its concept• The administrators don’t have control over what happens on

each client local repository

A Short History of Git

• (1991-2002) – The Linux kernel changes to the software were passed around as patches and archived files.

• (2002) – The Linux kernel project began using a proprietary DVCS system called BitKeeper.

• (2005) – The relationship between Linux kernel and the BitKeeper broke down. After that Linux development community create their own tool named Git, based on what they learned using the BitKeeper.

Some Git Goals

• Speed• Simple design• Strong support for non-linear

development (thousands of parallel branches)

• Fully distributed• Able to handle large projects like the

Linux kernel efficiently (speed and data size)

Git Basics

• Snapshots, Not Differences• Nearly Every Operation Is Local• Git Has Integrity• Git Generally Only Adds Data• The Three States

Snapshots, Not Differences

Differences

http://git-scm.com

Snapshots, Not Differences

Snapshotshttp://git-scm.com

Nearly Every Operation Is Local

• You can work offline as look the history, commit some changes or create branchs

Git Has Integrity

• Git generate a SHA-1 hash for each commit associated a file

• Git realize a checksum everytime is tried to store some change. So Git knows when something was changed or the file is corrupted

24b9da6552252987aa493b52f8696cd6d3b00373

Git Generally Only Adds Data

• Doing commits regularly it is very difficult to get the system to do anything that is not undoable or lose some change

• Let us more comfortable to experiment changes, because is easy to recover a previous version

The Three States

CommittedStagedModified/Untracked

http://git-scm.com

Lets start use Git

So, what are we going to do?

• Configure• Create a

Repository• Passing through

the 3 States• Branch• Merge• Log

• Alias• Diff• Tag• Ignoring Files and

Folders• Getting a Remote

Repository• Basic Workflow

Configure

• Download and Install Git: http://git-scm.com/

• You just need the Git Bash to work

git config --global user.name "Your Name Here"# Sets the default name for git to use when you commit

git config --global user.email "your_email@example.com"# Sets the default email for git to use when you commit

Username

Email

Create a Repository

git init

Create the repository

cd your_folder_name

Access your project directory

git status

Check the repository current status

All your repository data and configuration is stored on a hidden folder named .git on your repository’s root

Passing through the 3 States

git commit –m ‘This is my awesome comment’

Save objects on local repository

git add (general_comand/file_name/folder_name/…)

Add objects to staging area

touch file_name/folder

Create or Change a file/folder From Nowhere/Repository Working Directory

How is the status now?

How is the status now?

How is the status now?

Working Directory Staging Area

Staging Area Repository

How is the status now?

Adding, Removing and Renaming

git add .

Stages new and modified, without deleted

git add -A

Stages All

git add -u

Stages modified and deleted, without new

git rm file_name/

Stages a removed file

git rm -r folder_name/

Stages a removed folder

git mv old_file_name new_file_name

Stages a renamed file

.gitignore

*.tmpx64/

Is a hidden file named .gitignore on your root’s repository that contains a list of all ignored files and folders, like:

Diff

git diff file_name

Compare the working directory with staging area

git diff HEAD file_name

Compare the working directory with local repository

git diff --cached file_name

Compare the index with local repository

git diff --name-status branch_1 branch_2

Compare the branchs showing just the status and file name

Custom Alias

git lol

Using the new alias

git config --global --add alias.lol "log --graph --decorate --pretty=oneline --abbrev-commit --all"

Create a new alias to show a log with graph

git config –-local -l

List all the local configurations

Branchs

git checkout –b branch_name

Create and Switch for a new branch

git branch

List all local branchs

git checkout branch_name

Switch for a existing branch

git push remote_name branch_name

Add a local branch for a remote repository

git pull remote_name branch_name

Update local branch from a remote branch

Working with Remote Repositories

Merges

git merge branch_name

Merge on the current branch changes made on another branch

Before merge

After merge

Merge ConflictsMaster

Merge conflict

Development

Resolving the conflict

git commit –a -m ‘Resolving merge conflicts’

Commit the file after resolve the conflict

Tags

git tag

List all tags

git tag -a tag_name -m 'message description'

Creating an annotated tag

git push origin v1.0

Sharing tags

git push origin --tags

All tags

Working with Remote Repositories

git tag -a v1.0 -m 'my version 1.0'

Git + Social Coding

Add and Pull a Remote Repository

git clone git@github.com:owner_repo/repo_name.git

Cloning a or repository

git remote add origin git@github.com:owner_repo/repo_name.git

git pull origin master

Actually what the clone command does is: remote add + pull

And actually what the default pull command does is: fetch + merge

Update local repository avoiding the amount of merges (fetch+rebase)git pull --rebase repo_name branch_name

Pushing to the Remote Repository

git push remote_name branch_name

Pushing for the remote repository

git push origin master

Basic Workflo

w

http://nakedstartup.com/2010/04/simple-daily-git-workflow

Others helpful (or not) commands

git shortlog -s -n

List of Git Contributors

git ls-files -s file_name

Show the SHA1 of a file staged

git hash-object file_name

Show the SHA1 of a file modified

git checkout --file_name

Discard changes of a file

Others helpful (or not) commands

git reset HEAD file_name

Undo git add before commit

git log --pretty=oneline

One line logs

git status -s

Short status

git reset --hard HEAD~1

Delete the last commit before Push

Questions

Look more…

• Using SSH security connections• Git Cheat Sheet Grey• http://git-scm.com