Normal users, sure. But I wonder what fraction of developers use regularly/have ever used commandline tools?

I can certainly see some environments in which you might never be exposed, in things like Visual Studio, XCode, or Eclipse.

My recollection is that Windows has never really had a good native shell, but I've not used win7 for any length of time, and I'm not sure if Powershell ever became a thing. There's also cygwin, but I'm pretty sure that'll be more remote still.

I have a suspicion that the reason Github appears so mac-dominated is because of the pain of dealing with git under windows, especially when tortoise-git wasn't around/stable. Then again, there always seemed to be a heavy rails/OSX connection, but I don't know exactly where that comes from.