Professional Git

Brent Laster

• Publisher: Wrox
• Year: 2016
• Print ISBN: 9781119284970
• eBook ISBN: 9781119285007
• Edition: 1
• Topic: Computer Science
• Subtopic: Software Development
• Index: Computer Science

Leverage the power of Git to smooth out the development cycle

Professional Git takes a professional approach to learning this massively popular software development tool, and provides an up-to-date guide for new users. More than just a development manual, this book helps you get into the Git mindset—extensive discussion of corollaries to traditional systems as well as considerations unique to Git help you draw upon existing skills while looking out—and planning for—the differences. Connected labs and exercises are interspersed at key points to reinforce important concepts and deepen your understanding, and a focus on the practical goes beyond technical tutorials to help you integrate the Git model into your real-world workflow.

Git greatly simplifies the software development cycle, enabling users to create, use, and switch between versions as easily as you switch between files. This book shows you how to harness that power and flexibility to streamline your development cycle.

• Understand the basic Git model and overall workflow
• Learn the Git versions of common source management concepts and commands
• Track changes, work with branches, and take advantage of Git's full functionality
• Avoid trip-ups and missteps common to new users

Git works with the most popular software development tools and is used by almost all of the major technology companies. More than 40 percent of software developers use it as their primary source control tool, and that number continues to grow; the ability to work effectively with Git is rapidly approaching must-have status, and Professional Git is the comprehensive guide you need to get up to speed quickly.

Part I
Understanding Git Concepts

• CHAPTER 1: What Is Git?
• CHAPTER 2: Key Concepts
• CHAPTER 3: The Git Promotion Model

Chapter 1
What Is Git?

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WHAT'S IN THIS CHAPTER?

• A brief introduction to Git and its history
• The different ways to find and access Git
• Types of applications that incorporate Git
• The advantages of using Git
• The challenges of using Git

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In this chapter, you'll be introduced to Git and will learn about it from a product perspective—what it is, why it's used, the different kinds of interfaces you can use with it, and the good parts and challenging parts of working with it. This will provide an important foundation for understanding the technical details that follow in the subsequent chapters.

If I were to summarize what Git is in one paragraph, it would go something like this:

Git is a popular and widely used source management system that greatly simplifies the development cycle. It enables users to create, use, and switch between branches for content development as easily as people create and switch between files in their daily workflow. It is implemented using a fast, efficient architecture that allows for ease of experimentation and refinement of local changes in an isolated environment before sharing them with others. In short, it allows everyday users to focus on getting the content right instead of worrying about source management, while providing more advanced users with the ability to record, edit, and share changes at any level of detail.

In short, Git is different—really. When you're experienced with using Git and understand it, this will make you feel empowered and productive. When you're new to Git, and trying to understand it, you will encounter a model that will lead you to think differently about managing content in source control.

To illustrate, there's an old saying that “when all you have is a hammer, everything looks like a nail.” When all you have is a traditional centralized source management system, everything looks like a file-by-file change that is expensive to branch.

Not so with Git. Git is one of those nice tools that actually allows users to focus on developing content and simplifying workflows. It's not just another tool in the toolbox, it is the toolbox. It contains all of the tools you need to manage tracking anything from a few files for a single user to projects spanning hundreds of users and a huge scope, such as the Linux kernel. Today, many large companies use Git. It's free, it's powerful, it scales, and its model works when used as designed.

Git also has a certain “feel” that's appealing to many people. Git is structured more like a series of individual utilities that you can run against your content, similar to how users work with operating systems. However, it doesn't try to be the system; it gives users ultimate control over their content, even to the point of being able to update history if needed. Git manages basic units that equate to directory structures rather than individual files, so content that extends across file and directory boundaries can be managed together. Git simplifies branching, to a point where creating, merging, or deleting branches becomes nearly as quick and easy as creating, merging, or deleting files. It also provides a local environment with full source management control that can be updated independently of the shared, public environment.

Given that it is different from other source code management (SCM) systems, it's useful to understand how Git originated. The following section includes some of its history.

HISTORY OF GIT

Git has its roots in the development environment for the Linux kernel. In the early 2000s, the team working on the kernel began using a proprietary distributed source control system called BitKeeper (sometimes abbreviated as BK). The team was initially allowed to use this system for free. Over time, differences of opinion developed around the use of BK to the point that the owner of that system revoked the free use of the product. At that time (in 2005), Linus Torvalds, the creator of Linux, set out to create a new system that maintained the distributed ideal, but also incorporated several additional concepts he had been working with. Perhaps most importantly, he wanted it to provide the fast performance that a project on the scope of the Linux kernel would need. Thus the motivation and ideas for what became Git came into being.

Development began in early April of 2005, and an initial release was ready by July. Originally, there was an idea of purposing Git as a toolkit that could have other systems implemented on top of it. However, over time, it has been made into a full-fledged SCM in its own right.

If you're wondering about the name, there are multiple definitions for the word Git, but all of them imply a negative connotation about a person. Git was given its name by its creator. Linus jokingly stated that he named all his projects after himself.

For those interested in learning more about this phase of Git development, detailed historical information is available on the Internet.

INDUSTRY-STANDARD TOOLING

From these early beginnings, Git has grown to become an industry-standard tool. Of course, industry standard is a relative term. Nevertheless, based on nearly any criteria, Git fits. It is used across all levels of industry. Huge projects, such as the Linux kernel, are managed in it, and also mandate its use (see the following list). It is a key component of many continuous integration/continuous delivery pipelines. Demand for knowledge about it is ever increasing. Commercial and open-source projects and applications recognize that if they require source management services, they have to integrate with Git. Projects and companies using Git include

• Google
• Facebook
• Microsoft
• Twitter
• LinkedIn
• Netflix
• O'Reilly
• PostgreSQL
• Android
• Linux
• Eclipse

As with any sufficiently successful open-source technology, an entire ecosystem has sprung up around Git. This point is worth discussing for a moment. The basic tool that is Git has given rise to a seemingly endless number of applications to further help users who want to work with it—most named with some wordplay based on git. If you start discussing Git with someone, you may hear such names as GitHub, Gitolite, Easy Git, Git Extensions, EGit, and so on. To the uninitiated, it can be challenging to understand how each one of these names relates to the original Git tooling. To help clarify some of the confusion, I'll give you an overview of how the different offerings are categorized.

THE GIT ECOSYSTEM

Broadly, you can break down the Git-based offerings into a few categories: core Git, Git-hosting sites, self-hosting packages, ease-of-use packages, plug-ins, tools that incorporate Git, and Git libraries.

Core Git

In the core Git category, you have the basic Git executables, configuration files, and repository management tooling that you can install and use through the command line interface. (These can be installed from https://git-scm.com/downloads.) In addition to the basic pieces, the distributions usually include some supporting tools such as a simple GUI (git gui), a history visualization tool (gitk), and in some cases, an alternate interface such as a Bash shell that runs on Windows. The distribution for Windows is now called Git for Windows. Similarly there is a ported version of Git for OS/X. This version can be installed directly from the git-scm.com site, or via the Homebrew package manager or built via the MacPorts application.

When installing on Lin...

Table of contents

• Cover
• Title Page
• Introduction
• PART I: UNDERSTANDING GIT CONCEPTS
• PART II: USING GIT
• End User License Agreement