Matt Gauger - Git & Github web414 December 2010

Git &Github

Housekeeping•Slides & blog post will be available at: blog.mattgauger.com•Follow me: twitter.com/mathiasx•More resources at the end & linked in my blog post

Giving not just one talk,not two, but three talks in December!

MKE PHP User’s Group: PHP vs. Rails Dec 14th 6PM

MKE Ruby User’s Group:What’s new and great in Rails 3 Dec 20th 7PM

About Me

I am not an expert.

This talk is aimed at beginners.

So please do play along.

Introducing:A ﬁctional user thathas never used git.

Get Stuff Done.

Github is the hook.

jQuery prototypescriptaculous mootoolsyui3

Ruby on Rails web.py &Symfony many othersDjango

But why is Github so popular?

Let’s take a look.

Github is popular becauseit optimizes for the things developers need to do

It doesn’t get in the way.

And because it’s fun.

Back to our user.

Found Heard on Pete’s blog.

The user wants to addgRaphaël graphs to Heard

Graphs are cool.

The user signs up for Github.

They go back and click “Watch”

Clicks “Fork”

And somethingmagical happens.

(Parents please make your children leave the room or cover their eyes during this part of the program.)

We now have ourown fork of Heard.

Forks are copies.

The ﬁrst step in usingGithub after signing up is to install git (duh)

This is left as an exercise for the reader!

http://git-scm.com

Meanwhile, in ourAccount Settings

Sidenote:What are SSH keys and why do I need them?

SSH is a secure communicationsmethod that uses public/private key encryption.

You generate two keys:a public and a private key.

Github knows that only you have the private key

So every time we communicate with the Github server, we don’thave to type a password!

Generate a key pair

$ ssh-keygen

Generates id_rsaand id_rsa.pub inyour .ssh/ folder

The .pub ﬁle isthe public key

ssh-rsaAAAAB3NzaC1yc2EAAAABIwAAAQEAx5qfMKhR/+PQcOw2P/ho36T/aorbGJxiNwLDjrLenFK122nrdjdAKJtBVqCLd2Doagd0iEOFFhMhdJ8hNZ3depupx3JAiCswCBMsL4orjfX1suyR5DA5QyHpf5OGZdKacutlD3l/CsPq2IH2coQnwlnZTVo6oEBklweTHImx0ElfTaqdYOZZ+SW4NQ01aj+6jNb4g4D9BqcIcXA/XDL6B4ﬁ6FtbJo4HlfjAt/YYOKhxblKYRvBuftfJ0Mrn4Nl1twY5tZ23gDG+4LZli7fdoFzRN3EjuEhD/Mg61D1JISQyHDsJQWbOnAdnV3wko8HV9F1D65wpYprHZqueI2xo4w== mathiasx@banshee.local

Copy this key and paste itinto your Github settings.

We’re now ready to hack!

Go back to ourfork of Heard

$ git clone git@github.com:mathias-presentation/Heard.gitCloning into Heard...remote: Counting objects: 22, done.remote: Compressing objects: 100% (22/22), done.remote: Total 22 (delta 7), reused 0 (delta 0)Unpacking objects: 100% (22/22), done.

$ git clone URI

Creates a local version ofthe project from the server

$ lsCHANGELOG conﬁg.php table-tracks.sqlLICENSE heardsync.php tracks.phpREADME init.php

Now we have the code

The user makes somechanges to the code.

User wants git to trackchanges to those ﬁles.

For our purposes, theuser ﬁnds this command:

$ git commit

$ git commit# On branch master# Changed but not updated:# (use "git add ..." to update what will be committed)# (use "git checkout -- ..." to discard changes in workingdirectory)## modified: config.php# modified: init.php# modified: tracks.php#no changes added to commit (use "git add" and/or "gitcommit -a")

Nothing happened.

“no changes added to commit”

Nothing happened?

(use "git add" and/or "git commit -a")

git add ﬁlename

git commit -a

The -a is for all

That is, commit everythingthat changed in the project.

The user types in

$ git commit -a

And is dropped into.. a text editor?

Default text editor.

Likely vim on Linux or Mac OSX.

To change it to something more user-friendly:

$ git conﬁg core.editor "nano"

The text editor is fora commit message.

Git is already tracking the exact changes to ﬁles.

Your commit messageshould be more abstract.

That boils down to

What did youactually do?

In one line or so.

A good commit messagewill help later when you’re trying to remember what you did.

So now we break the narrative.

Show a lot of things happening at once,remind everyone of whats going on!And with every shot show a littleimprovement,to show it all would take too long!Thats called a montage! MONTAGE!Ooh, we want a montage! MONTAGE!

A typical commit:

$ git commit -am "Added the gRaphael libraryto be loaded, but havent integrated it yet."[master 1a4014f] Added the gRaphael libraryto be loaded, but havent integrated it yet. 3 ﬁles changed, 3 insertions(+), 3 deletions(-)

We don’t have to commit all changes at once

[edit some files]$ git add config.php$ git add init.php$ git add filename

git status

$ git status# On branch master## Changes to be committed:# (use "git reset HEAD ..." to unstage)## modified: config.php# modified: init.php## Changed but not updated:# (use "git add ..." to update what will be committed)# (use "git checkout -- ..." to discard changes inworking directory)## modified: tracks.php#

Were only going to commit the changes in the conﬁg.php and init.php

$ git commit -m "A little refactoring."[master 6dd5c59] A little refactoring. 2 ﬁles changed, 2 insertions(+), 2 deletions(-)$ git status# On branch master## Changed but not updated:# (use "git add ..." to update what will be committed)# (use "git checkout -- ..." to discard changes inworking directory)## modiﬁed: tracks.php#no changes added to commit (use "git add" and/or"git commit -a")

Notice that tracks.php is still waiting to be committed.

The “staging area”

To see the history of our project, type:

$ git log

$ git logcommit e47cd6eb917d2a68ec6d1197a38faa1a1ff5e564Author: Matt Gauger <matt.gauger@gmail.com>Date: Thu Dec 9 14:27:04 2010 -0600 Add some newlines after error output.commit 4cce3dff9c8d03b7db1710f7addaa7d556921a44Author: raster <pete@rasterweb.net>Date: Sun Nov 14 11:38:50 2010 -0600 Minor changes, still learning git[truncated]

You may be asking

“How do I upload mychanges back to Github?”

$ git push

$ git pushCounting objects: 5, done.Delta compression using up to 4 threads.Compressing objects: 100% (3/3), done.Writing objects: 100% (3/3), 335 bytes, done.Total 3 (delta 2), reused 0 (delta 0)To git@github.com:mathias/Heard.git fb2cc2b..e47cd6e master -> master

And to get changes from the server:

$ git fetch

What happens if I screw up?

Throw away the changes

$ git reset --hard HEAD

Be careful with this, obviously

What if I only want to throwaway changes to one ﬁle?

$ git checkout -- init.php$ git checkout HEAD init.php

We’ve covered the most common commands.

Now what?

Our user sends a PullRequest back to Pete.

This asks Pete to merge in their changes.

Pete can use the Githubweb interface to merge those changes in.

Which means our user hascontributed back to Heard,as they originally intended.

What about GUI clients?

“The commandline is scary!”

Mac•Tower.app: http://www.git-tower.com/•Gitbox: http://www.gitboxapp.com/•GitX: http://gitx.frim.nl/

Linux•git cola: http://cola.tuxfamily.org/•gitk is included in git-core•giggle for diffs: http://live.gnome.org/giggle

This has been a very brief introduction to Git.

Come see me for freeGithub stickers after.

Thank you for your time.

Further Reading:• help.github.com•gitref.org•progit.org/book•www.gitready.com

http://blog.mattgauger.com	1112
http://coderwall.com	24
http://localhost	5
http://mathias.github.com	4
http://posterous.com	3
http://liveweb.archive.org	1
http://www.netvibes.com	1

Matt Gauger - Git & Github web414 December 2010

by Matt Gauger on Dec 10, 2010

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Matt Gauger - Git & Github web414 December 2010 — Presentation Transcript