mitchellh/vagrant — comment on commit 467542ef8d7bf6bff93d9acf20108fd844b528f0
File: lib/vagrant/driver/virtualbox.rb line 39
By mitchellh:

I actually did use `\\` at first but that actually resulted in a literal `\\` in the string. I don't really know lol.

As for the double quotes for the `ENV[]`, Ruby doesn't care as long as its in an interpolation thing `#{}` :)