I imagine they (Google) doesn't consider this information private so here's the bulk of an email I got listing prep material and topics: http://pastebin.com/iXGzfkBL
Yep, I got a very similar e-mail before the on-site. There was some more in some e-mails before the phone interviews, like links to man pages, some (public on YouTube) Google videos, and some sample coding problems.
FWIW, I bought "Programming Pearls (2nd Edition)" and "Advanced Programming in the UNIX Environment (3rd edition)". "Programming Pearls" was definitely a good choice.
My problem with APUE is that it includes so much detail about platforms I'm not likely to be exposed to. It's probably a great reference for that stuff (it's almost a rosetta stone for unix programming), but it could probably be half as long without the "extraneous" stuff.
There is a now classic Steve Yegge blog post that gives a recommendations and advice (a lot of Google recruiters actually point candidates towards it to prepare). Although it's over six years old now it's still pretty much on point.
I just started at Google two weeks ago (as a SWE, not SRE, though), and I found Cracking the Coding Interview to be the most helpful book for preparing for interviews in general. I also used Programming Interviews Exposed, which is comparable, but CtCI has a little more content.
yes also would be interested in this. Also even a vague example of what one of the questions might look like (not asking for an exact interview question)
I've found that this website contains a lot of onsite-like coding questions and is generally really good for practicing problem solving (it's basically Project Euler but for programmers): oj.leetcode.com/problems/
Edit: To clarify, this is for SE, not SRE.