Linux Interview Questions Part- 1

Top Linux Interview Questions for Learners.

1. What is Linux?

Explain the difference between Linux, a kernel, and an operating system.

2. Explain the File System Hierarchy in Linux.

Discuss the structure and purpose of directories like /bin, /home, /etc, /var, /usr, and others.

3. What are the basic file permissions in Linux?

• How does the permission model work for files and directories in Linux?

• Explain the significance of r, w, and x for users, groups, and others.

4. How do you change file permissions?

• Command to change file permissions: chmod

• Command to change ownership: chown

• What are symbolic and numeric modes for permissions?

5. What are the differences between sudo and su?

• Describe when and why you would use sudo over su and vice versa.

6. What is a shell?

• Explain the concept of a shell in Linux.

• Name different types of shells, like Bash, Zsh, etc.

• How do you change the default shell?

7. Explain the purpose of environment variables in Linux.

• What are some common environment variables like PATH, HOME, and USER?

• How do you create and manage environment variables?

8. How do you check the current running processes?

• Discuss commands like ps, top, htop, and pgrep.

• How would you kill a process using kill, killall, or pkill?

9. What is the difference between hard links and soft (symbolic) links?

• Describe how hard links and symbolic links are created.

• When should you use each type?

10. Explain package management in Linux.

• What are some package managers used in Linux, like apt, yum, dnf, and pacman?

• How do you install, update, and remove packages?

11. How do you search for files in Linux?

• Explain the use of find and locate commands.

• How do you search for a specific text within files using grep?

12. How do you view the content of a file?

• Explain the use of commands like cat, less, more, head, and tail.

• How do you follow a log file in real-time using tail -f?

13. What is cron and how do you schedule jobs using it?

• Explain the format of a cron job.

• How do you view, add, or remove cron jobs for a user?

14. What are system logs and where are they stored?

• Explain the purpose of logs and the location of system logs in /var/log.

• How do you use journalctl to view system logs?

15. What is the difference between df and du commands?

• How do you check disk usage and available space?

• What are some useful flags for these commands?

16. How do you manage services in Linux?

• How do you start, stop, restart, and check the status of services using systemctl and service commands?

17. What is the difference between a terminal emulator and a shell?

• Describe the relationship between terminal emulators (like GNOME Terminal, Konsole) and shells (like Bash, Zsh).

18. How do you compress and extract files in Linux?

• Explain how to use commands like tar, gzip, bzip2, zip, and unzip.

• What’s the difference between gzip and bzip2?

19. How do you redirect output in Linux?

• Explain input/output redirection using >, >>, and 2> for standard output and error streams.

• How do you use pipes (|) to chain commands together?

20. What is SSH and how do you use it to connect to a remote server?

• How do you set up an SSH connection and copy files using scp or rsync?

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Advanced Linux Interview Questions (Optional)

21. Explain how networking works in Linux.

• What commands are used to check network interfaces (ip, ifconfig) and troubleshoot network issues (ping, netstat, traceroute)?

22. What is iptables and how is it used in Linux?

• Explain the role of iptables in firewall configuration.

23. What is a Linux kernel module?

• How do you list, load, and unload kernel modules using commands like lsmod, modprobe, and rmmod?

24. What is LVM (Logical Volume Management)?

• Explain how LVM is used to manage disk storage dynamically and how to create, extend, and reduce LVM volumes.

25. How do you monitor system performance in Linux?

• Discuss tools like vmstat, iostat, sar, and free.

• How do you track CPU, memory, and disk performance?