Tuesday, February 9, 2010

Book Review: Pragmatic Version Control Using Git

I have not posted a lot on this blog recently so I thought I would add a quick book review. I recently (about a fortnight ago) finished Pragmatic Version Control Using Git by Travis Swicegood, published by the Pragmatic Programmers / Pragmatic Bookshelf.

I come from a Subversion background. In fact, only recently I think I really started to hit my stride with the version control system. But as sometimes happens I was late to the party. An upstart version control system named Git, first popularized as the new version control system for the Linux kernel, is becoming increasingly popular. A key difference between Git and Subversion is that Git is a distributed version control system control. A git repository is designed to be cloned, changes are pulled between repositories and at anyone time multiple developers may be working on their own individual, complete copies of the repositories before refining their commit history and pooling their changes.

So although Git uses many of the same principles I am used to in Subversion, such as branches and tags, it is a fundamentally a different approach to source control, and requires a good book to explain it.

Travis Swicegood's Pragmatic Version Control Using Git has a lot in common with the previously released Pragmatic Version Control Using Subversion. Physically it is exactly the same dimensions in length and breadth and at 224 pages is about 30 pages longer. The pages are thick, high quality acid-free and mostly recycled paper. The print is grey scale and each chapter has a few diagrams or screenshots, but an average of ten or so plain command and output listings.

The first chapter in the book talks about the basic of what version control is and what some of the terminology means. Chapter two talks about how to get Git installed on your system and some configuration you might need to do. Chapter three sets up an example project has a brief overview of all the common actions, like adding files, committing them and creating a release branch. The detail is light, since the topics are covered in later chapters of the book.

Chapters four through nine delves into the details of the common operations you are likely to use in Git: Adding and committing files, using branches, examining the log, working with remote repositories, organisation and repository administration. The focus is on building on the knowledge form chapter three and exploring useful commands and when they might be useful.

Chapters ten and eleven cover migration to Git from other source control versions and you can set up a Git server.

As in Pragmatic Version Control using Subversion, there is a very useful Command Summary and Recipies section as one of the appendices. Long after you have finished the book you might find yourself returning there to get a quick refresher on the keystrokes required for different Git commands you may not commonly use, such as Rebasing.

The book is written in a very conversational style and is consequently very easy to read. There are couple of areas (for example, during the chapter about rebasing) where more detail and discussion would have been helpful in avoiding confusion.

In comparison to the Pragmatic Version Control with Subversion book, less time is spent discussing conventions of use. This may in part be because Git codifies some of the conventions of Subversion - for example tags and branching - into actual functionality. It would have been nice however to cover in more depth some of the other issues of convention that arise from having a distributed source control system. 

The examples in the book are easy to follow, but they are also a bit simplistic. Each chapter starts with instructions on how to clone the repository required for that chapter from the author's Git hosting site.

Overall I rate the book highly for newcomers committed to using Git. Readers already familiar with Subversion will breeze through the book. Those that are completely new to source control may struggle. Was it worth buying for me? Yes.

Let me know if you have any further questions about the book in the comment area.

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