Problem
You are interviewing a DevOps Engineer for a Meta security-infrastructure role. The goal is to assess whether the candidate can use basic Linux commands to investigate common host-level security and reliability issues on a production server that supports internal services such as Meta’s TAO-backed applications.
Design a short command-line assessment focused on practical triage, not memorization. The candidate should explain what command they would run, why they would use it, and what output they would expect.
Requirements
Create a set of Linux command questions that cover these areas:
- Process inspection: identify high-CPU or suspicious processes.
- File system usage: find large files, check disk space, and inspect permissions.
- Networking: verify listening ports, active connections, and DNS resolution.
- Logs and troubleshooting: inspect recent system or application logs.
- Users and permissions: determine who is logged in, current identity, and sudo-related access.
- Service health: check whether a daemon is running and how to restart or inspect it.
Example prompts
- How would you find the top CPU-consuming processes on a Linux host?
- Which command would you use to see what process is listening on port 443?
- How would you check recent authentication failures?
- How would you find files larger than 1 GB under
/var?
- How would you confirm the current user, groups, and effective privileges?
Deliverable
For each prompt, provide:
- the preferred command,
- one acceptable alternative,
- a brief explanation of the output,
- and one security-relevant follow-up question.
Keep the focus on Linux fundamentals that matter in incident response, host hardening, and production debugging.
