Mike McQuaid - Git in Practice

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I first heard of Git probably nine years ago, around the end of 2005, right around when v1.0 was being tagged. Reading through my friend Mikes book, it amazes me just how much has changed in what Im only now realizing has been nearly a decade of history.

At the time I was introduced to Git, it was still very much more of a collection of tools for content management and less a version control system. It was installed as hundreds of commands such as git-update-index instead of the single git command we now call. In fact, in my first exposure to it, I used it at work as a transport mechanism for media content, instead using Perforce to version-control the code we wrote around Git.

It fascinated me how clean and simple the data model was and how easy it was to manipulate to do anything you wanted, not simply what was prescribed and intended. Equally fascinating was how difficult it was to learn. It took my friend weeks to drill into me how this thing worked, but after that I was totally hooked and have spent most of the decade since helping people use it and understand it.

If youre still struggling with Git, this book does a great job of leading you through the basics in a straightforward manner. If youre already comfortable with those, will help you see other ways you could be using Git to make your teams workflows simpler or more effective. Although Ive spent a lot of time learning and explaining to others the elegant simplicity of the data model, Ive never helped run a huge open source effort such as Homebrew as Mike has, and that experience is invaluable in explaining more advanced and complex workflows as Mike describes here.

I hope you enjoy this book, and I hope you use it to understand and enjoy the amazing benefits that a tool like Git can bring to your daily development life. Im proud of Mike for taking on this challenge and for producing a great book on a tool that has made the transition over the past decade from being an interesting hobbyists script to an essential part of millions of software developers daily lives.

S COTT C HACON

A UTHOR OF P RO G IT

As all good software engineers will agree: version control is important. I was first introduced to version control while studying computer science at university and dabbling with open source in my free time. CVS and Subversion started being used for managing our small pieces of coursework, group projects, and larger open source projects we interacted with. Initially it all felt a bit like overkill: why do I need this when Im working by myself? It only took a few personal screw-ups for me to understand why version control is so important.

I was introduced to Git in 2006 while working on audio drivers for the Linux kernel at a summer internship. It was a fairly terrifying beast in those days: incredibly fast compared to its competitors, impressive in how it managed almost everything offline, but with an arcane user interface that was full of jargon. The jargon has decreased, but everything else remains fairly similar: Git is fast, impressive, and confusing.

My first few jobs after graduating found most companies still using Subversion. Git was one of those things used by kernel hackers and the particularly hardcore open source crowd, and it wasnt ready for mainstream use yet. I liked the glimpse Id had of it, so I continued using it stealthily with git svn, a bridge that allows you to access Subversion repositories using Git. Eventually GitHub came along and convinced people that Git could be easy to use, and I was able to use Git more regularly. I became a maintainer of the Homebrew Mac OS X package manager, and more employers and clients began to use GitHub.

I think because I was a relatively early adopter of Git and the type of person who needs to know how things work, I ended up helping others with Git: first at my own workplace and then through training courses, talks, and helping others in the open-source community. Eventually I was contacted by another publisher about writing a Git book, and I contacted Manning to ask if I could write with them. The result is Git in Practice: a book that takes you from intermediate- to advanced-level Git tools and workflows that Ive found useful while working as a software engineer.

There are many people without whom this book wouldnt be a reality. First, Id like to thank Dan Maharry, my development editor at Manning, who kept me motivated and provided excellent feedback that has resulted in a far better book than I could have created on my own. Additionally, many others who work at and with Manning have helped me along the way, particularly Jay Bryant, Michael Stephens, Bert Bates, Benjamin Berg, Glenn Burnside, Tiffany Taylor, and Ozren Harlovic.

Thanks to Scott Chacon for his great book Pro Git, which helped me while I was learning Git, and for agreeing to write the foreword.

Thanks to Karsten Strbk for his technical proofread of the manuscript shortly before it went into production, to Gerd Koenig for his help, and to the following reviewers who provided invaluable feedback: Alan Lenton, Art Bergquist, Chris Couchoud, Clare Macrae, Corey Gallon, Gregor Zurowski, Jean-Pol Landrain, John Guthrie, Ken Fricklas, Nathan Davies, Patrick Toohey, Rick Umali, Tarin Gamberini, and Zarko Jovicic.

Thanks to Linus Torvalds, without whom this wonderful version control system would not exist, and to Tom Preston-Werner, Chris Wanstrath, and PJ Hyett for starting GitHub, without which Git wouldnt have nearly the widespread usage it does today. Also thanks to them for hiring me!

Finally, Id like to thank my wife Lindsay for putting up with my occasional whining about writing this book and for her understanding about how much time I had to spend on it.