How do you "check out" code?

Question

I've never really worked with a lot of people where we had to check out code and have repositories of old code, etc. I'm not sure I even know what these terms mean. If I want to to start a new project that involves more than myself that tracks all the code changes, does "check out" (again, don't know what that means), how do I get started? Is that what SVN is for? Something else? Do I download a program that keeps up with the code?

What do I do?

It will all be in house. No Internet for storing code.

I don't even know if what I am asking for is called source control. I see things about checking out, SVN, source control, and so on. I don't know if it is all talking about the same thing or not. I was hoping to use something open source.

Answer 1

So, a long time ago, in the bad old days of yore, source control used a library metaphor. If you wanted to edit a file, the only way to avoid conflicts was to make sure that you were the ONLY one editing the file. What you'd do is ask the source control system to "check out" that file, indicating that you were editing it and nobody else was allowed to edit it until you made your changes and the file was "checked in". If you needed to make a change to a checked out file, you had to go find that freakin' developer who'd had everythingImportant.conf checked out since last Tuesday..freakin' Bill...

Anyway, source control doesn't really work like that anymore, but the language stuck with us. Nowadays, "checking out" code means downloading a copy of the code from the code repository. The files will appear in a local directory, allowing you to use them, compile the code, and even make changes to the source that you could perhaps upload back to the repository later, should you need to. Even better, with just a single command, you can get all the changes that have been made by other developers since the last time you downloaded the code. Good stuff.

There are several major source control libraries, of which SVN (also called Subversion) is one (CVS, Git, HG, Perforce, ClearCase, etc are others). I recommend starting with SVN, Git, or HG, since they're all free and all have excellent documentation.

You might want to start using source control even if you're the only developer. There's nothing worse than realizing that last night the thousand lines of code you deleted as useless were actually critically important and are now lost forever. Source control allows you to zoom forwards and backwards in the history of your files, letting you easily recover stuff that you should not have removed, and giving you a lot more confidence about deleting useless stuff. Plus, fiddling around with it on your own is good practice.

Being comfortable with source/revision control software is a critical job skill of any serious software engineer. Mastering it will effectively level you up as a professional developer. Coming onto a project and finding that the team keeps all their source in a folder somewhere is an awful experience. Good luck! You're already on the right path just by being interested!