Getting Git

Intros

  • Name
  • Job/Role
  • Length of time at Rackspace
  • What you hope to get from this class
  • Previous experience with version control tools

Learning Objectives

  • Learn what version control is
  • Recognize what Git and Github are and how they are used
  • Practice day to day Git usage
  • Collaborate online through GitHub

What is Version Control

  • A time machine for files and projects
  • Snapshots/checkpoints of the project as a timeline
  • Also referred to as revision control

Why use Version Control?

What should we use Version Control for?

  • Different kinds of files
    • Text files
      • Scripts, config files, software, etc.
    • Binary files (with caveats)
    • Images / logos (with caveats)
  • Files that are shared with others
    • Anything that can be changed by multiple folks
  • Managing the flow of changes
    • Deploying known versions of files

What is Version Control

Graphic from http://www.git-tower.com/learn/git/ebook/command-line/basics/what-is-version-control

Nomenclature

  • Version control
  • Source control
  • Revision control

Use Case 1:

  • Multiple people (team members) working on the same stuff

Use Case 2:

  • Keeping track of changes as you manage a system

Use Case 3:

  • Tracking / managing common configs across multiple systems

War Stories

Work Flow

  • Get / open a repository
    • Pull down changes shared with you by others
  • Create a branch for your work
  • Do some work
    • Check in (commit) changes periodically
  • Push your branch to a server to share your work with others
  • Merge branches to bring changes into the main "master" branch
  • Lather, rinse, repeat

Work Flow

  • Each step in that workflow maps to a Git command
    • or a set of Git commands
  • You can map your own workflow activities to Git
    • It is really flexible
  • We will work on labs that illustrate all these workflow steps

What is Git?

What is Git

  • From the web: Git is a free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency.
  • Git is a suite of tools for you to implement version control
    • The core stuff is command line
    • GUIs are available (more on that later)

Installing Git

What is a repository?

  • A repository is the place that stores all the data for your version controlled directory
    • database for all the versions, metadata, file contents, etc.
  • A repository can live on a local machine, cloud server, or other nebulous device
  • Repositories can be cloned and shared

Git Commands - init

  • Get / open / create a repository
git init .

Git Commands - add

  • Do some work
    • Check in (commit) changes periodically
  • To commit your changes first you have to stage them
    • Tell Git which changes you will be committing
git commit -m "my cool comment"
git add my_file.txt image.jpg

Git Commands - rm

  • Remove a file (or files) from the repo
git rm my_file.txt image.jpg

Git Commands - status

  • Find out the status of the repo
git status

Git Commands - reset

  • Unstage a change
  • (after an add)
git reset new_file.txt

Git Commands - undo an edit

  • Undo all edits to a file 
  • Great caution is advised here
git checkout -- changed_file.txt

Lab 1

https://github.com/jeremyprice/GettingGit/blob/master/lab01.md

Branching, Merging, and Conflicts

Workflow Continued

  • Working linearly on a project doesn't scale well
  • We need to be able to work on parallel sets of changes
  • Thankfully, we have branching and merging

Branching and Merging Illustrated

Branching

  • Creating a branch called nice_feature

 

  • Make that branch the active branch
git branch nice_feature
git checkout nice_feature

Branching

  • Shortcut: Creating a branch called nice_feature and make it active
git checkout -b nice_feature

Merging Branches

  • Merging branches asks Git to take the changes from one branch and put them in the other
  • Merge changes from nice_feature into master
git checkout master
git merge nice_feature

A note about the master branch

  • The master branch is special
  • It is considered the core branch that changes are merged into
  • By convention, master is usually a known state of the files in the repository
  • It is not the only branch you can merge changes into
  • From Git's perspective it is just any old branch

Conflicts

  • Merge conflicts happen when you try to merge changes that overlap from one branch to another 
  • Example: in your README file 
    • Branch A: Hello world!
    • Branch B:Goodbye world!
  • Git can't tell which one it should go with, so it tells you to pick

Lab 2

https://github.com/jeremyprice/GettingGit/blob/master/lab02.md

GitHub for Collaboration

GitHub

  • GitHub is a web-based Git repository hosting service
    • Centralized repository
  • Social coding features
    • pull requests
    • documentation (markdown)
    • wikis
    • issue tracking
    • small websites
    • history browsing
    • code reviews
  • Example: https://github.com/jeremyprice/GettingGit

Lab 3

https://github.com/jeremyprice/GettingGit/blob/master/lab03.md

Other Topics

GUI Clients

Good list of GUI apps:

Demo of Git GUI

SourceTree

Further reading

Desk Reference

Cheat Sheet

http://byte.kde.org/~zrusin/git/git-cheat-sheet-large.png

Your feedback is important to us

  • Please take a moment to fill out a brief evaluation for this class:
  • Go to mylearn.rackspace.com
  • Scroll down to My Tasks on your myLearn welcome page
  • Click on the evaluation link for this class
  • Fill out the evaluation then submit

We appreciate your feedback!

Getting Git

By Rackspace University

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Getting Git

Learning Git and GitHub

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