Meta Linux, Networking & Scripting interview questions

The question that separates people who have debugged a hung rollout from people who have read about one. The interesting half is not the signal, it is PID 1.

A staple of every networking round, and the follow-up is always about TLS termination. Knowing which layer sees what decides most of the answer.

The oldest question in systems interviewing and still the best, because it is unbounded: the interviewer stops you when you run out of depth, and where you stop is the score.

The question that reveals whether someone knows what load average actually counts on Linux. It is not a CPU metric, and that single fact resolves the whole thing.

The scripting round in disguise. The constraint is the question: it exists to see whether you stream or whether you load, and everything else is about whether the script is safe to run twice.

The two-syscall duet behind every process on the box. The follow-ups live in what survives the transition, and candidates who skip that fail the next question.

SIGKILL writes no stack trace and the application cannot defend itself. The verdict is already sitting in the kernel ring buffer, and reading it precisely is the skill being priced.

tcpdump copies packets to userland; eBPF aggregates inside the kernel next to the event. Know which hook runs where, what a verifier log is telling you, and when XDP drops for free.

The classic ephemeral port exhaustion question. Most candidates know the phrase TIME_WAIT; far fewer know which side accumulates it and why the popular fix is dangerous.

Two different resources produce the same errno, and the second one is invisible unless you know to look. One command distinguishes them.

A beginner question with a senior follow-up hiding in it. Once you know a hard link is a second name for an inode, log rotation and backup behaviour both stop being mysterious.

Everyone recites the four letters. The scoring answer walks each packet across the wire and knows the places the exchange silently dies.

Interviewers use this to sort memorised trivia from people who have chased a slow lookup. Three roles, one bit, and the caching rules most candidates repeat incorrectly.

A routine cloud operation with three layers that can quietly disagree. The strong answer is an ordered procedure you could run during business hours, without a reboot.

The answer is yes, and then the real question starts. Asymmetric routing and silent drops punish anyone who treats the routing tables as one flat list.

A growing backlog of sockets waiting for the application to close its side usually points at lifecycle handling. Here is the hunt from ss output to the pool timeout that caused it.

Most hand-written units boot in dev and die in production. The gap is Type selection, restart policy, and the drop-in workflow vendors expect you to respect.

A one-line mistake that locks you out of the obvious fix. The fast recovery teaches more about the permission model than any man page will.

Most candidates can recite the flags. The scored part is proving you can capture on a saturated box without adding load, then read the file afterward like evidence.

Two authentications happen in every SSH session and most candidates narrate only one. Knowing who proves what, and where your agent socket ends up, is the scored material.

Every ops engineer schedules jobs; few can say which shell cron uses, where stdout lands, or why percent signs delete half a command. Those gaps are exactly what interviews test.

The swap-used graph is the least informative memory metric on the box. Here is what swappiness actually weights, which numbers to watch instead, and the policy worth defending.

The signature is unmistakable once seen: handshakes complete, then the connection freezes at the same byte count every time. Here is the probe sequence and the fixes, ranked.