Version Control with Git
Wolfman and Dracula have been hired by Universal Missions (a space services spinoff from Euphoric State University) to investigate if it is possible to send their next planetary lander to Mars. They want to be able to work on the plans at the same time, but they have run into problems doing this in the past. If they take turns, each one will spend a lot of time waiting for the other to finish, but if they work on their own copies and email changes back and forth things will be lost, overwritten, or duplicated.
A colleague suggests using version control to manage their work. Version control is better than mailing files back and forth because:
Nothing that is committed to version control is ever lost. This means it can be used like the "undo" feature in an editor, and since all old versions of files are saved it's always possible to go back in time to see exactly who wrote what on a particular day, or what version of a program was used to generate a particular set of results.
It keeps a record of who made what changes when, so that if people have questions later on, they know who to ask.
It's hard (though not impossible) to accidentally overlook or overwrite someone's changes: the version control system automatically notifies users whenever there's a conflict between one person's work and another's.
Version control is the lab notebook of the digital world: it's what professionals use to keep track of what they've done and to collaborate with other people. Every large software development project relies on it, and most programmers use it for their small jobs as well. And it isn't just for software: books (like this one), papers, small data sets, and anything that changes over time or needs to be shared can and should be stored in a version control system.
Version control is useful even for a project with only a single contributor, because it provides a reliable way to keep the project software up to date on multiple separate computer systems.
Prerequisites
In this lesson we use Git from the Unix Shell. Some previous experience with the shell is expected, but isn't mandatory. The Git bash shell on Windows and git from a Mac shell should work just as well.