Linux Interview Questions (Beginner → Intermediate)

🐧 Linux Interview Questions (Beginner → Intermediate)

🔹 Basic Linux Questions

1. What is Linux?
2. Difference between Linux and Windows
3. What is a Linux distribution? Name a few.
4. What is the Linux kernel?
5. What is a shell?
6. What are the most common Linux shells?
7. What is the root user?
8. What is the home directory?
9. Difference between / and /root
10. What is the purpose of /etc directory?

🔹 File & Directory Commands

1. What does ls do?
2. Difference between ls -l and ls -a
3. What is the use of pwd?
4. How do you create and delete files?
5. Difference between rm and rm -rf
6. What is cp vs mv?
7. What does touch do?
8. How do you view file contents?
9. Difference between cat, less, and more
10. What is head and tail?

🔹 Permissions & Ownership

1. What are Linux file permissions?
2. What does rwx mean?
3. What is chmod?
4. Difference between numeric and symbolic permissions
5. What is chown?
6. What is chgrp?
7. What is umask?
8. What is SUID, SGID, and sticky bit?

🔹 Process Management

1. What is a process?
2. Difference between process and thread
3. What does ps command do?
4. What is top?
5. Difference between top and htop
6. What is kill?
7. What is kill -9?
8. What is a daemon process?
9. What does nice do?

🔹 Disk & File System

1. What is a filesystem?
2. Difference between ext4 and xfs
3. What does df show?
4. What does du show?
5. What is mounting?
6. What is /etc/fstab?
7. Difference between hard link and soft link
8. What is inode?

🔹 Networking

1. What is an IP address?
2. Difference between TCP and UDP
3. What does ifconfig or ip a do?
4. What is ping?
5. What is netstat or ss?
6. What is SSH?
7. Default SSH port
8. What is SCP?
9. What is firewall in Linux?

🔹 Package Management

1. What is a package manager?
2. Difference between apt, yum, and dnf
3. How do you update a system?
4. What is a repository?
5. What is rpm?
6. What is dpkg?

🔹 Text Processing

1. What is grep?
2. Difference between grep and egrep
3. What is sed?
4. What is awk?
5. What is a pipe (|)?
6. What is redirection (> and >>)?

🔹 Boot & System

1. What happens during Linux boot?
2. What is GRUB?
3. What is systemd?
4. What is systemctl?
5. Difference between service and process
6. What is runlevel / target?

🔹 Environment & Variables

1. What is an environment variable?
2. Difference between $PATH and $HOME
3. How do you set a variable?
4. What is .bashrc?
5. What is .bash_profile?

🔹 Logs & Troubleshooting

1. Where are system logs stored?
2. What is journalctl?
3. How do you check disk space issues?
4. How do you find large files?
5. How do you troubleshoot high CPU usage?

🔹 Scenario-Based Questions (Very Important)

1. A server is slow. How do you troubleshoot?
2. Disk is full. What steps do you take?
3. A service is not starting. What do you check?
4. How do you find which port a process is using?
5. How do you schedule a task in Linux?
6. Difference between cron and at
7. How do you change the hostname?
8. How do you secure SSH?
9. 
   

🔹 Linux + DevOps / Security (Bonus)

1. What is Docker in Linux?
2. What is SELinux?
3. What is AppArmor?
4. Difference between SELinux and firewall
5. What is sudo?
6. Why Linux is preferred for servers?
7. What is bash scripting?
8. What is a shebang (#!)?
9. What is CI/CD?
10. Why Linux is important for cybersecurity?