From the linked shell style guide:

> Indentation is two spaces. Whatever you do, don’t use tabs.

The recent obsession with 2 space indents is boggling to me. I find it much more difficult to read (especially in long blocks of code with lots of indentation switches) and I'm not even visually impaired.

They also apparently really don't like tabs, which I find interesting. Personally, I was converted to the tabs camp after learning how much better tabs are for accessibility. I'm surprised that Google of all places doesn't take that more seriously.