GDG LAGOS – Getting Deep with Git – What Git is not!

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GDG LAGOS – Getting Deep with Git – What Git is not!

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git-slides

Slides for the git event at the CCHub Nigeria.

On Github nanyaks / git-slides

GDG LAGOS

Getting Deep with Git

Nanyak Loknan S.
@nanyaks
What is Git and why all the 'hype'?
Feel free to ask your questions!

A bit of a background

Git was created in 2007 by Linus Torvalds ...

A bit of a background

I said 'a bit' ...
see wikipedia

What is Git?

Simply put, git is a source code management system.
Source control / Version control is the management of changes to documents, computer programs and other collections of information
see wikipedia article for more!

What Git is not!

Neither is it...

Why should I care?

Git makes your life easier
Yes, it does!
Has this ever happened to you?
Now you don't need to worry about it!
That in itself is a winner for version control.

Some more benefits of git

Data redundancy and replication

Since there are multiple full repositories on multiple machines (instead of one central repository), the risk of project loss due to server failure or some other catastrophe is much lower.

High Availability

High availability -- Server down? Network down? No problem. Work in your repo (commit, view history, branch, etc) to your heart's content. Try that with Subversion!

One central .git directory

Only one .git directory per repository -- Versus a .svn in every subfolder, which, as you may know from painful personal experience, can lead to problems.
This might not seem like a benefit but ask those that used other version control systems

Superior disk utilization and network performance

Git efficiently compresses the objects in the .git directory, saving you space.

Collaboration Friendly

Git makes it easy to collaborate on projects with groups of contributors. And with great services like Github, Git's collaboration friendliness is even further magnified.

Now the fun stuff!

Installing Git

Windows

Installing Git on windows

Mac

Or via the MacPorts 
sudo port install git-core +svn +doc +bash_completion +gitweb

Generating SSH keys on Mac

SSH keys are a way to identify trusted computers, without involving passwords everytime you push to Github. The link below will walk you through generating an SSH key and adding the public key to your GitHub account.

Linux

Red Hat based systems (Fedora, CentOS) 
yum install git-core
Debian based systems (Ubuntu) 
sudo apt-get install git

History

Git is really all about your history.
It creates a specialized filesystem to store your code history and when you tell it to, it records snapshots of your code repository.
Do note that git is a command line tool that has GUI frontends, though very convenient, does not show the full power of git. So once we understand the concepts, we'll move to a gui tool

Configuring Git

$ git config --global user.name "Tunji Bello Ebube"
$ git config --global user.email user@email.com
Some other config values that may be interesting
core.editor => your_editor_name_here
color.ui => true

Initializing a Git repository

Navigate into the folder you'd like git to start tracking and run
$ git init

Concepts to remember

A Few of my favourite things

  • Git branch
  • Git add
  • Git commit
  • Git diff
  • Git log
  • Git stash

A closer look a branches

A single commit in the repository has the following format
Pointer to that root tree and all the commit metadata
Making some commits to the repository
Many commit trees and their associated metadata
This is how the repository looks at the moment.
Showing the master branch and its representation
When we branch by running 
$ git branch testing
We now have our repo looking like...
Multiple branches
HUH?...What is 'HEAD'
Its just a pointer...
We checkout the new branch: 
$ git checkout testing
...and voila!
Doing another commit
Showing 'testing' ahead of 'master' by one commit!
Just a sneak peak!

Some advanced concepts

  • Git objects
  • Git log Options
  • Git reset
  • Git rebase
  • Git cherry-pick

Git Objects

Git objects are entirely composed of:

  • Blobs
  • Trees
  • Commits
  • Tags

The Git refspec

A refspec maps a branch in the local repository to a branch in a remote repository. This makes it possible to manage remote branches using local Git commands and to configure some advanced git push and git fetch behavior.

Formal spec

[+]src:dst
src

The pattern for references on the remote side

dst

Where the references will be written to locally

Git Log

Some interesting options:
  • --grep
  • --author
  • --since, --after, --until, --before
  • --merges (--min-parents=2)
  • --pretty=full

Thank you!

Read Github Doc.