What is the difference between all the different types of version control?


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After being told by at least 10 people on SO that version control was a good thing even if it's just me I now have a followup question.

What is the difference between all the different types of version control and is there a guide that anybody knows of for version control that's very simple and easy to understand?


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    Eric Sink has a good overview of source control. There are also some existing questions here on SO.


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    We seem to be in the golden age of version control, with a ton of choices, all of which have their pros and cons.

    Here are the ones I see most used:

    • svn - currently the most popular open source?
    • git - very hot since Linus switched to it
    • mercurial - some smart people I know swear by it
    • cvs - the one everybody is switching from
    • perforce - imho, the best features, but it's not open source. The two-user license is free, though.
    • visual sourcesafe - I'm not much in the Microsoft world, so I have no idea about this one, other than people like to rag on it as they rag on everything from Microsoft.
    • sccs - for historical interest we mention this, the great-grandaddy of many of the above
    • rcs - and the grandaddy of many of the above

    My recommendation: you're safest with either git, svn or perforce, since a lot of people use them, they are cross platform, have good guis, you can buy books about them, etc.

    Dont consider cvs, sccs, rcs, they are antique.

    The nice thing is that, since your projects will be relatively small, you will be able to move your code to a new system once you're more experienced and decide you want to work with another system.


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    To everyone just starting using version control:

    Please do not use git (or hg or bzr) because of the hype

    Use git (or hg or bzr) because they are better tools for managing source code than SVN.

    I used SVN for a few years at work, and switched over to git 6 months ago. Without learning SVN first I would be totaly lost when it comes to using a DVCS.

    For people just starting out with version control:

    • Start by downloading SVN
    • Learn why you need version control
    • Learn how to commit, checkout, branch
    • Learn why merging in SVN is such a pain

    Then switch over to a DVCS and learn:

    • How to clone/branch/commit
    • How easy it is to merge your branches back (go branch crazy!)
    • How easy it is to rewrite commit history and keep your branches
      up to date with the main line (git rebase -i, )
    • How to publish your changes so others can benefit

    tldr; crowd:

    Start with SVN and learn the basics, then graduate to a DVCS.


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    I would start with:

    Then once you have read up on it, download and install SVN, TortoiseSVN and skim the first few chapters of the book and get started.


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    Version Control is essential to development, even if you're working by yourself because it protects you from yourself. If you make a mistake, it's a simple matter to rollback to a previous version of your code that you know works. This also frees you to explore and experiment with your code because you're free of having to worry about whether what you're doing is reversible or not. There are two major branches of Version Control Systems (VCS), Centralized and Distributed.

    Centralized VCS are based on using a central server, where everyone "checks out" a project, works on it, and "commits" their changes back to the server for anybody else to use. The major Centralized VCS are CVS and SVN. Both have been heavily criticized because "merging" "branches" is extremely painful with them. [TODO: write explanation on what branches are and why merging is hard with CVS & SVN]

    Distributed VCS let everyone have their own server, where you can "pull" changes from other people and "push" changes to a server. The most common Distributed VCS are Git and Mercurial. [TODO: write more on Distributed VCS]

    If you're working on a project I heavily recommend using a distributed VCS. I recommend Git because it's blazingly fast, but is has been criticized as being too hard to use. If you don't mind using a commercial product BitKeeper is supposedly easy to use.


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    The answer to another question also applies here, most importantly

    Jon Works said:
    The most important thing about version control is:

    JUST START USING IT

    His answer goes into more detail, and I don't want to be accused of plaigerism so take a look.


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    The simple answer is, do you like Undo buttons? The answer is of course yes, because we as human being make mistakes all the time.

    As programmers, its often the case though that it can take several hours of testing, code changes, overwrites, deletions, file moves and renames before we work out the method we are trying to use to fix a problem is entirely the wrong one and the code is more broken than when we started.

    As such, Source Control is a massive Undo button to revert the code to an earlier time when the grass was green and the food plentiful. And not only that, because of how source control works, you can still keep a copy of your broken code, in case a few weeks down the line you want to refer to it again and cherry pick any good ideas that did come out of it.

    I personally (though it could be called overkill) use a free Single user license version of Source Gear Fortress (which is their Vault source control product with bug tracking features). I find the UI really simple to use, it supports both the checkout > edit > checkin model and the edit > merge > commit model. It can be a little tricky to set up though, requiring you to run a local copy of ISS and SQL server. You might want to try a smaller program, like those recommended by other answers here. See what you like and what you can afford.


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    Mark said:

    git - very hot since Linus switched to it

    I just want to point out that Linus didn't switch to it, Linus wrote it.


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    If you are working by yourself in a Windows environment, then the single user license for SourceGear's Vault is free.


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    We use and like Mercurial. It follows a distributed model - it eliminates some of the sense of having to "check in" work. Mozilla has moved to Mercurial, which is a good sign that it's not going to go away any time soon. One con, in my opinion, is that there isn't a very good GUI for it. If you're comfortable with the command line, though, it's pretty handy.

    Mercurial Documentation Unofficial Manual


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    Just start using source control, no matter what type you use. What you use doesn't matter; it's the use of it that is important


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    Like everyone else, SC is really dependant on your needs, your budget, your environment, etc.

    At its root, source control is designed to provide a central repository of all your code, and track who did what to it when. There should be a complete history, and you can get products that do full changelogs, auditing, access control, and on and on...

    Each product that is out there starts to shine (so to speak) when you start to look at how you want or need to incorporate SC into your environment (whether it's your personal code and documents or a large corporations). And as people use them, they discover that the tool has limitations, so people write new ones. SVN was born out of limitations that the creators saw with CVS. Linus wanted something better for the Linux kernel, so now we have git.

    I would say start using one (something like SVN which is very popular and pretty easy to use) and see how it goes. As time progresses you may find that you need some other functionality, or need to interface with other systems, so you may need SourceSafe or another tool.

    Source control is always important, and while you can get away with manually re-numbering versions of PSD files or something as you work on them, you're going to forget to run that batch script once or twice, or likely forget which number went with which change. That's where most of these SC tools can help (as long as you check-in/check-out).


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    See also this SO question: