Git

Version control for professionals

Miguel D. Quintero

migueldavidq@gmail.com

Problems with not having version control.

Trouble following the code.
Having folders named with: version 1, version 2, version 3
Difficulty in collaboration

Centralized vs Distributed

Centralized

Everyone must connect to a central server.
You can't work offline.
Writing policies.
Changes affect everyone.
Creating branches is very expensive, time-consuming or tedious.
Branches affect everyone because they are global.
You'd need naming policies so as not to interfere with others.
You wait until you have something stable to upload to the repository.
You never create something stable on the first try.

Distributed

They're all equally important.
You can work offline.
You must gain confidence and trust in others.
Changes only affect you.
Collaboration - Make changes without affecting others.
Experiment and branch out the code as you wish.
You don't have to ask for write permission.
There is no single point of failure, and the information is naturally replicated.

Git Qualities

Designed to handle large projects.
It's extremely fast.
Cryptographic authentication of history.
Very simple and compact file format.
100% distributed.
Can be synchronized by any means.

Git is for the big ones

Linux kernel has more than 22,000 files.
Linux has been using Git for several years, averaging 4.5 merges per day.
Showing the differences of the entire kernel, 74,000 commits, takes about 7 seconds (cold cache) or 2.3 seconds (warm cache).
The CVS repository of the Mozilla Project is 3GB, in Subversion it is 12GB in fsfs format. In Git it's 300MB.

Where Git comes from. History of Git: Linus Torvalds

In 2002, the Linux kernel project began using BitKeeper, a proprietary software.
In 2005 it was no longer offered free of charge.

Speed
Simple
Distributed
Non-linear development (branches)

"unpleasant person" - "persona desagradable"

Git as "the stupid content tracker"

What is Git

Git is a distributed source code control system or SCM.

Knowing who's touched what and when.
Control over how our project has changed over time.
Going back to previous versions quickly.
Version control through labels.
Security: all internal data structures are signed with SHA1. You cannot change the code without detection.
It improves our ability to work as a team.
Extremely efficient merging and branching.

What is a git repo ?

Getting Started with Git

git config

        
$ git config --global user.name "USERNAME"
$ git config --global user.email "EMAIL@EMAIL.com"

Creating a git repo

        
$ git init
$ git add .
$ git commit -m "init"

git init DIRECTORY

Staging

Working with Git

        
$ git add README.md
$ git commit -m "DESCRIPTIVE MESSAGE"
$ git status

$ git add .

$ git status -u

Git Add

        
$ git add README.md
$ git add *.txt
$ git add docs/*.txt
$ git add docs/
$ git add --all
$ git add .

Git Status

        
$ git status



$ git status -h

Git Commit

        
$ git commit -m  "DESCRIPTIVE MESSAGE"



$ git commit -h

What is a hash?

a127204a4f2db81e9ce29491641f15911ef3d1f1
f413107df4f80b7eff8508c4730bf175b1910f5a
30acbef642822c526b32552e09a335bb7452f938
bbcaf8ef8f70b1a3a2e33329b8cadf8bde965f29

History

        
$ git log

$ git log --summary
$ git log --oneline
$ git log --follow --oneline FILE
$ git log --pretty=format:'%h - %cn - %s' --abbrev-commit

View changes

        
$ git diff

$ git diff --staged

Git Checkout

        
$ git checkout master

$ git checkout COMMIT
$ git checkout COMMIT FILE
$ git checkout HEAD hello.py

Undoing Changes

        
$ git revert COMMIT

$ git checkout COMMIT
$ git checkout COMMIT FILE

$ git reset FILE

Summary

        
$ git config
$ git init
$ git add
$ git commit
$ git status
$ git log
$ git diff
$ git revert
$ git checkout
$ git reset

Using Branches

Git Branch

        
	$ git branch
	$ git branch BRANCH-NAME

	$ git branch -d BRANCH-NAME
	$ git branch -D BRANCH-NAME
	$ git branch -m NEW-NAME

Git Branch

        
	$ git branch BRANCH-NAME

	$ git checkout BRANCH-NAME

	$ git checkout -b BRANCH-NAME

Git Merge

        

		$ git merge BRANCH-NAME

		$ git merge --no-ff BRANCH-NAME

Remote

Working with remote repos

Git remote

        
$ git remote
$ git remote -v
$ git remote add NAME URL
$ git remote rm NAME
$ git remote rename OLD-NAME NEW-NAME

Git remote

        
	https://github.com/Mayccoll/Linux.git

	ssh://user@host/path/to/repo.git

	git@github.com:Mayccoll/Linux.git

Git clone

        
$ git clone	https://github.com/Mayccoll/Linux.git

$ git clone	ssh://user@host/path/to/repo.git

$ git clone	git@github.com:Mayccoll/Linux.git

Git Clone

        
  git clone git@github.com:mayccoll/Linux
  ___ _____ ___ __________ ________ _____
   1    2    3    4          5        6

   1. Command
   2. Argument

   3. host user
   4. host
   5. User
   6. Folder

Git Push

        
$ git push BRANCH

$ git push origin master

Git fetch

        
$ git fetch REMOTE

$ git fetch REMOTE/BRANCH

$ git fetch origin

Git Pull

        
$ git pull REMOTE

=

$ git fetch REMOTE
$ git merge REMOTE/BRANCH

Git Branch

        
$ git branch -a

$ git branch -r

Summary

        
$ git branch
$ git checkout -b
$ git merge
$ git remote
$ git clone
$ git push
$ git fetch
$ git pull

Learn

Atlassian Tutorial

Gitimmersion

learn Git Branching

[es]

Pro Git

Utils

Git

Git Extras

Git stats

Gitignore

Github Ribbons

GUIs

GUI Clients