Shaumik Daityari - Jump Start Git, Second Edition

Tips provide helpful little pointers.

Notes are useful asides that are relatedbut not criticalto the topic at hand. Think of them as extra tidbits of information.

... pay attention to these important points.

Warnings highlight any gotchas that are likely to trip you up along the way.

In my freshman year in college, I started work on my first intranet application. The files in the main directory of the partially functioning application looked something likeFigure 1-1.

Looking at the file names in this directory, you can see that I used some very similar names, such as exam.php, exam1.php and examfile.php. The purpose of that naming convention was to create new versions of my application without losing the old, working logicin case the new ideas failed! I assumed that, because I understood what each of those files did, it should be fine to have a bunch of similarly named files.

However, there were two flaws in that thinking. Firstly, anyone else examining this code wouldnt be able to make sense of this mess. Secondly, after a few months, even I was struggling to recall what each version of these files was for. Clearly, I needed a better system for managing the various versions of my files.

If I had this much trouble working on a small, personal project, imagine how difficult it must have been for larger software projects, with thousands of files and contributors distributed all over the world! Developers once used emails to coordinate changes among team members. When they made changes to a project, they would each create a difffile with all their changes and email it to the lead developer, who would incorporate them into the project if everything worked properly.

When youre working on the same files as other developers, keeping track of what youve changed and trying to merge it with work done by your peers becomes very difficult. It can result in a lot of confusion and time wasting.

Imagine another situation, where youre working on an idea and your boss wants to see what youve already completed. Ideally, youd want to be able to do the following:

• stash away the changes and revert to the last stable state
• show your boss the latest completed work
• resume your work with the current state once thats done

All of the situations Ive described above give rise to the need forwhats known as version control. So lets find out what that is.

Version control (or revision control) is a system that records changes to a file or a group of files and directories over time, so that you can review or go back to specific versions later. Over the course of this book, Ill demonstrate how this works. But first, lets examine in more detail what version control is.