Introduction

Prepare for your Linux interview rounds with these top questions and clear, concise answers. This guide covers system commands, administration basics, troubleshooting, and practical Linux skills for freshers and experienced candidates.

Linux Interview Questions and Answers

1. What is Linux?
An open-source, Unix-like operating system used for servers, desktops, and embedded systems.

2. What are the advantages of Linux?
Free and open-source, secure, stable, customizable, and supports a wide range of hardware.

3. What is the Linux kernel?
The core component of the Linux OS managing system resources and hardware communication.

4. What is a shell in Linux?
A command-line interpreter that allows users to interact with the system.

5. Name some commonly used Linux shells.
Bash, Zsh, Ksh, Tcsh, and Fish.

6. How do you check the current working directory?
Using the pwd command.

7. How to list files in a directory?
Using the ls command.

8. How to view hidden files in Linux?
Using ls -a.

9. How do you change file permissions?
Using the chmod command.

10. How do you change file ownership?
Using the chown command.

11. What is the command to view the contents of a file?
Using cat, less, or more.

12. How do you create a new file in Linux?
Using touch filename or echo > filename.

13. How to remove a file?
Using rm filename.

14. How to remove a directory?
Using rmdir directoryname or rm -r directoryname.

15. How to copy files in Linux?
Using cp source destination.

16. How to move files in Linux?
Using mv source destination.

17. What is a process in Linux?
An instance of a running program.

18. How to check running processes?
Using ps, top, or htop.

19. How to kill a process in Linux?
Using kill PID or killall processname.

20. What is the grep command used for?
To search for patterns in files.

21. How do you find the current user in Linux?
Using whoami or id.

22. How to check disk usage in Linux?
Using df -h.

23. How to check memory usage?
Using free -h.

24. How to display the last lines of a file?
Using tail filename.

25. How to display the first lines of a file?
Using head filename.

26. What are runlevels in Linux?
Modes that define system behavior, such as multi-user or graphical modes.

27. How do you change permissions recursively?
Using chmod -R permissions directory.

28. What is sudo in Linux?
Allows users to run commands with superuser privileges.

29. How to schedule tasks in Linux?
Using cron jobs and crontab.

30. What is a symbolic link?
A shortcut pointing to another file or directory.

31. How to create a symbolic link?
Using ln -s target linkname.

32. How to check network connectivity?
Using ping, ifconfig, or ip a.

33. What is SSH?
Secure Shell, used for secure remote logins.

34. How to compress files in Linux?
Using tar, gzip, or zip.

35. How to extract compressed files?
Using tar -xvf, gunzip, or unzip.

36. How to check system uptime?
Using uptime command.

37. What is the difference between soft link and hard link?
Soft links point to the filename, hard links point to the inode.

38. How to display environment variables?
Using printenv or env.

39. What is fstab?
File system table containing disk mount information.

40. How to mount a file system?
Using the mount command.

41. How to unmount a file system?
Using the umount command.

42. What is the root user?
The administrative user with full system access.

43. How to switch users in Linux?
Using the su command.

44. How to view system logs?
Checking /var/log directory and using tail.

45. What is swap space?
Space used for virtual memory when RAM is full.

46. How to check open ports?
Using netstat -tuln or ss -tuln.

47. How to check system hardware information?
Using lshw or lscpu.

48. How to change the hostname in Linux?
Using hostnamectl set-hostname newname.

49. What is vi editor?
A text editor available in Linux for editing files.

50. How to exit vi editor?
Press Esc, type :wq to save and exit, or :q! to exit without saving.

Frequently Asked Questions