Top Linux Interview Questions for DevOps Engineers

As a DevOps engineer, Linux forms the backbone of most infrastructure. Here are the most commonly asked Linux interview questions you should be prepared for:

1. What is Linux, and why is it important for DevOps?

   • Be ready to explain why Linux is widely used in server environments for its stability, security, and scalability.

2. How do you manage file permissions in Linux?

   • Know the chmod, chown, and permission structure (read, write, execute) for files and directories.

3. How do you check system resource usage (CPU, memory, disk)?

   • Familiarize yourself with commands like top, htop, free, df, and vmstat for resource monitoring.

4. What is the significance of the SSH command in Linux?

   • Understand how SSH provides secure remote access to servers and enables safe file transfers.

5. How do you troubleshoot network issues in Linux?

   • Review commands like ping, netstate, ifconfig, nslookup, and traceroute for diagnosing network problems.

6. How do you create and manage users and groups in Linux?

   • Practice using commands like useradd, usermod, passwd, and groupadd for managing users and groups.

7. How do you manage software packages in Linux?

   • Be comfortable with package managers like apt, yum, and rpm for installing, updating, and removing software.

8. What is the purpose of /var/log/ Linux?

   • Understanding how log files are stored /var/log/ is critical for system auditing and troubleshooting.

9. What is a kernel in Linux, and how does it interact with hardware?

   • Explain the role of the Linux kernel in managing hardware resources and processes.

10. How do you find files in Linux?

    • Know commands like find, locate, grep, and which for searching files and directories.

11. What is the use of the cron command in Linux?

    • Understand how to schedule tasks using cron jobs and the syntax for setting them up with crontab.

12. What are Linux daemons?

    • Be prepared to explain what background services (like httpd, sshd) are and how to manage them using systemctl or service.

13. How do you set environment variables in Linux?

    • Explain how to set environment variables using export, and where to define them permanently.

14. How do you mount and unmount filesystems in Linux?

    • Know how to use the mount and unmount commands and manage fstab for automatic mounting.

15. What is SELinux, and how does it improve security?

    • Be familiar with Security-Enhanced Linux (SELinux) and its role in enforcing security policies.