Rants, rambles, news and notes from another geek

Mastering My Machine Repaves With Git and PowerShell

You repave how often?

I’ve always been someone who likes regularly rebuilding my Windows machines. (See this post or this post for some ancient history on this.) I know this isn’t needed as much as it used to be, but I still find myself starting to get that itch anywhere from 6-weeks to 3-months after I last flattened the box.

I’m convinced that part of this is due to my willingness to try out new apps, hack on things, mess with my registry, try beta drivers, etc. Say what you will… Those things make me happy!

So rather than curtail those things, I just figure out ways to get around it. As I like to explain to my wife, “What I really enjoy is bending computer to my will.”

Since I’ve been a part of Visual Studio, I’ve been using Hyper-V based machines more than ever. I’ve been a “do your development in VMs” guy for a long time came from my time in consulting and services). And here in DevDiv, it is faster and easier to just pull a nice new already flattened “Windows7 + yesterday’s VS11 Ultimate” VHD than it is to reinstall VS. So that’s what we all do.

(We are very fortunate that this is common enough that we have great big servers full of these VHDs, generated by our build labs, and you can just pull the one you want.)

But when I get to a new machine, there are a bunch of programs that I like to have handy:

  • Git - For CodePlex, GitHub or just a quick little local repo and required for this whole process to work
  • Vim - my “it always works” editor
  • 7-zip - the only Windows zip tool you ever need
  • KDiff3 - my “it always works” diff/merge tool
  • LinkShellExt - show symlinks & junctions in Windows explorer

But there are also a bunch of configurations that go with those things:

  • My PowerShell configuration
  • My Vim configuration
  • My gitconfig/gitignore files
  • etc

I’ve tried a number of different things over the years to get this all working but I think my current approach is finally The One. What I wanted to create, and what I now have, is something as simple as this:

  1. Download one thing
  2. Run it
  3. Win!

And I also wanted to be able to tweak it from any of my systems and have it easily available on the others.

I like the idea of having this stuff in a single easily available location. I’ve also always liked symbolic links, junction points, etc. as a way of making things look like they are where they are expected, even if they’re not. That probably comes from my *NIX background, where I first learned about them.

Hosted on GitHub

Here’s the short form of what I do with a new box: I download and install the most recent msysgit, then I pull my dotfiles repository from GitHub, and finally I run a couple of scripts. That’s it.

Since GitHub doesn’t really have any restrictions on what I put there, and since their isn’t anything private in any of these files, it is a perfect place to host this content. The repository has three main parts: the root, the .vim folder and the powershell folder.

In the root I keep various “dotfiles”. In the *NIX world, configuration of tools is almost always done by files in your $HOME directory that start with a dot (which makes them hidden). Examples include files like .vimrc, .bashrc, kdiff3rc, .gitconfig, etc.

The .vim folder is my configuration folder for Vim and Gvim. I use a vim plugin called pathogen which makes installing other plugins a snap, because it lets the plugin maintain its own local copy of the typical vim folder structure. Without pathogen, you have to unpack a vim plugin’s files into their respective syntax, ftdetect, etc. folders. But with pathogen, each bundle lives by itself, with its own folders, and pathogen merges them all together for vim.

The powershell folder contains all of my PowerShell scripts, my various profile scripts (I currently have three) and the modules that I load in. PowerShell modules are the same kind of thing as pathogen’s bundles. Each is in its own folder and they can be loaded by your profile.

Here’s where things get a little interesting. These programs expect to find their dotfiles in your $HOME directory. Vim, in fact, will be looking for an entire directory (called .vim of course) there. PowerShell on the other hand will be looking in $HOME\Documents\WindowsPowerShell.

So rather than copy things around, which would leave me in a crappy place when it came to updating things, I use symbolic links (and their directory counterpart on Windows called junction points). Basically symlinks add another pseudo-entry in the file system which makes the file appear as if it were in a new location. (This is as opposed to hardlinks which make the file have a real entry / second name which makes the file actually be at the new location. Subtly different, but different.)

What I want is for the following files to appear in the right place. (Note: I’m using the *NIX / PowerShell ~ to represent $HOME because that is getting tedious to type.)

  • $dotfiles\.vimrc » ~\.vimrc
  • $dotfiles\.gitconfig » ~\.gitconfig
  • $dotfiles\.gitignore » ~\.gitignore
  • $dotfiles\.vsvimrc » ~\.vsvimrc
  • $dotfiles\.kdiff3rc » ~\.kdiff3rc
  • $dotfiles\.vim » ~\.vim
  • $dotfiles\powershell » ~\Documents\WindowsPowerShell

Fortunately, the PowerShell Community Extensions (aka PSCX) module for PowerShell provides me with a few helper cmdlets to do this. So now I can set up those symbolic links with simple commands like these:

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PS> new-junction ~\.vim $dotfiles\.vim
PS> new-junction ~\Documents\WindowsPowerShell $dotfiles\powershell
PS> new-symlink ~\.vimrc $dotfiles\.vimrc
PS> new-symlink ~\.gitconfig $dotfiles\.gitconfig

But of course I didn’t want to have to remember that all the time, so I wrapped it up in another script that is in the same repository. (Hint: take a look in the /powershell/EnvSetup directory.)

Wrap up

If you want to see how it works, go check out the code. It is all in my dotfiles repository on GitHub. One of the really nice things about this approach is that since vim pathogen and PowerShell both let me place modules in-situ in their own folders, I can use git’s submodule feature to pick up the content, rather than cloning it into my own repository. Even pathogen loads in via a submodule. Win!

When I want to change some config setting, like a vim configuration or a new tweak to my PowerShell profile, I don’t have to think about it. I just change it, commit and push to GitHub. On my other machines I can just pull (or not) and get the update. Perfect!

You can see my dotfiles repository on GitHub to see the details.

Questions? Comments? Just ask.

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