Real command output, four plausible readings of it, and an explanation of why the other three are wrong. These are free to read here, no account. The full bank is 150 questions and 10 incident labs inside the app.
The other 140 are the hard ones. Multi-layer faults where the symptom is in one layer and the cause is in another, plus 10 incident labs in a shell that answers real commands — €7.99, 1 month of access. Field notes are free too.