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Timed mock tests and model answers written by working engineers, for every level from fresher to lead. Pick any of our 75 courses below.

Topic: Linux Administration. Questions are shared by related courses. View the Linux course → · Follow the Linux roadmap →

All Linux interview questions at a glance+

Fresher (0–3 years): Linux Support Engineer

  1. A server is slow. How do you investigate?
  2. Explain the Linux boot process briefly.
  3. How do you find which files are using the most space?
  4. Which command shows disk space usage of filesystems?
  5. How do you check whether the nginx service is running on a systemd system?
  6. What does chmod 640 file mean?
  7. Which command searches for text inside files?
  8. Which command shows listening ports?
  9. Where are most system logs on a systemd system read from?

Mid-level (3–8 years): Linux Administrator

  1. How do you harden a new Linux server?
  2. An application cannot connect to a database on another server. Troubleshoot.
  3. Explain processes, signals and how you stop a stuck process.
  4. Which file sets services to start at boot under systemd?
  5. Disable password login for SSH.
  6. A host resolves names slowly. Which file defines DNS resolvers?
  7. Run a script every day at 02:00.
  8. Extend a full logical volume online.
  9. Which tool enforces mandatory access control on RHEL?

Experienced (8–15 years): Senior Linux / Systems Engineer

  1. How would you plan an OS upgrade across a large fleet?
  2. A Linux server may be compromised. Your steps?
  3. How do you design monitoring for a Linux fleet?
  4. Manage configuration of 500 servers consistently.
  5. Kernel live patching mainly helps…
  6. Diagnose intermittent latency spikes at the kernel level.
  7. Tune a server for many concurrent connections.
  8. Detect unauthorised changes to system files.
  9. Immutable infrastructure means…