3. Version Control
Version control systems are also known as “revision control systems”, and “source control systems”. Version control is considered part of “software configuration management” (SCM) and there are also some more comprehensive SCM systems. Version control programs allow one to maintain various historical versions of one's data, retrieve earlier versions, and do other operations like branching or tagging.
This section will give the motivation for why you should start using version control for your software development, and will give a short demonstration using the Mercurial version control system. Feel free to skip this section if you're already drinking the version control kool-aid.