Managing Version History with Git

In this book, starting from Chapter 4, Setting Up Development Tools, we're going to be building a very simple user directory, which we've randomly named hobnob. We need a way for us to keep a versioned history of our code, so that if we've made some mistakes along the way, we can simply revert back to the last known good version and start again from there. This is known as version control (VC).

The simplest way to implement version control is to copy the entire codebase into date-stamped directories; however, this is tedious and may take up a lot of disk space. Instead, we can use a Version Control System (VCS) that'll manage these versions for us. We simply have to instruct the VCS when to create a snapshot of our code, and it will keep that version.

There have been many implementations of VCS, starting in 1972 with Source Code Control System (SCCS), which was superseded by Revision Control System (RCS, released in 1982), Concurrent Versions System (CVS, released in 1990), and Apache Subversion (SVN, released in 2000). Nowadays, we mainly use Git (released in 2005), a type of VCS known as Distributed VCS (DVCS).

Git was created by Linus Torvalds, who's also the creator of the Linux kernel. It is used to track changes in the development of the Linux kernel, as well as the tens of millions of repositories currently on GitHub. In this chapter, we will guide you through setting up and configuring Git, as well as explaining basic Git concepts, such as:

• Different states in Git
• Basic Git operations such as staging, committing, merging/rebasing, pushing, and pulling
• Implementing a parallel development workflow using a branching model proposed by Vincent Driessen, commonly known as Git flow
• Setting up a GitHub account to host our code remotely
• Understanding the workflow when working with others