Well, I think it's clear that the author is qualified to move beyond this stage of phone screening. So, the interviewer was at fault for not passing him, mainly due to a lack of technical knowledge imo and possibly and incomplete cheat sheet.
That said, I question how he's phrased some of the question/answer pairs. For instance, this is a phone interview so the questioner can't capitalize KILL in the signals question ("what is the name of the KILL signal?"), which makes me wonder how the question was actually phrased. It does strike me that SIGTERM is what the 'kill' command will send by default, which could have been the intent of the question.
He obviously still should have passed though, all of his answers indicated a good knowledge of the subject, and that's even if you consider them to be ultimately incorrect. I guess it's possible that op's tone didn't ingratiate him to the interviewer, but that's impossible to say with the information we have.