Unlock Linux Expertise: 100 Advanced Interview Questions for Senior-Level Engineers

Linux Basics and System Architecture

1. What is the difference between a Linux distribution and Unix?
2. Explain the Linux file system hierarchy.
3. What are the basic Linux commands you use daily, and how do they work?
4. Describe the process of booting a Linux machine.
5. What is the purpose of the kernel in Linux?
6. How does the Linux kernel interact with hardware?
7. What is a runlevel in Linux, and how do you manage it?
8. Explain the difference between hard links and soft links in Linux.
9. What are the key components of a Linux operating system?
10. How does Linux handle process scheduling?

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System Administration

1. How would you add a new user in Linux and assign it a specific group?
2. What are the different types of permissions in Linux?
3. Explain the significance of sudo and how it differs from su.
4. How do you check disk space usage in Linux?
5. What are cron jobs, and how do you schedule tasks using cron?
6. How do you monitor system performance on a Linux machine?
7. What is syslog, and how do you configure it?
8. How do you configure automatic backups in Linux?
9. What is the role of the init system, and what is its relationship with systemd?
10. How do you create and manage custom Linux users?

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Networking and Security

1. Explain the concept of network interfaces in Linux.
2. How do you configure network interfaces in Linux?
3. What is the purpose of iptables, and how do you configure basic firewall rules?
4. Explain the concept of SELinux, and how does it enhance Linux security?
5. How would you configure SSH key-based authentication in Linux?
6. What is the difference between iptables and firewalld?
7. How would you secure a Linux server from remote attacks?
8. How do you manage user authentication and password policies in Linux?
9. How do you secure a Linux web server?
10. What are Linux file permissions, and how can you set them to ensure secure access?

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Process Management and Performance Tuning

1. How does the Linux kernel manage process states?
2. How do you view and manage running processes in Linux?
3. What are the differences between fork() and exec() system calls in Linux?
4. How do you kill a process in Linux?
5. What is the purpose of nice and renice commands in Linux?
6. How would you identify and resolve high CPU utilization on a Linux system?
7. How do you check memory usage in Linux and optimize it?
8. What is swapping, and how does Linux handle memory management?
9. How would you optimize disk I/O performance on a Linux server?
10. What is the purpose of OOM Killer in Linux, and how does it work?

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Shell Scripting and Automation

1. How do you write a bash script to automate a task in Linux?
2. What is the significance of shebang (#!) in Linux scripts?
3. How do you handle command-line arguments in a shell script?
4. What are variables in bash scripting, and how do you use them?
5. How would you use loops in bash scripting?
6. How do you handle conditional statements in bash scripts?
7. How would you create a function in a bash script?
8. What is the purpose of pipes and redirection in Linux?
9. How do you debug a bash script in Linux?
10. How do you schedule tasks using at and cron in Linux?

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Package Management

1. How do you install, update, and remove packages in Debian-based systems (using apt)?
2. How do you install, update, and remove packages in Red Hat-based systems (using yum or dnf)?
3. What is the role of package managers in Linux?
4. How do you configure repository sources in Linux?
5. What is the difference between a package and a source in Linux?
6. How do you manage dependencies when installing software in Linux?
7. What is dpkg in Debian-based systems, and how is it used?
8. How do you rollback a package installation in Linux?
9. How would you configure automatic updates in Linux?
10. How do you manage third-party repositories in Linux?

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Linux File System and Storage

1. How do you create and manage file systems in Linux?
2. What is the purpose of LVM (Logical Volume Manager) in Linux?
3. How do you manage disk partitions in Linux?
4. What is RAID, and how can you configure it in Linux?
5. How do you mount a network drive (e.g., NFS, SMB) in Linux?
6. What are extended attributes, and how are they used in Linux file systems?
7. How would you recover a corrupted file system in Linux?
8. What are the mount options available in Linux, and how do you use them?
9. How do you check disk health and perform diagnostics in Linux?
10. Explain how to perform disk encryption in Linux.

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Advanced Linux Topics

1. What is the role of containers in Linux (e.g., Docker)?
2. How does containerization differ from virtualization in Linux?
3. How do you create a custom Linux kernel?
4. What is Linux namespaces, and how do they relate to containers?
5. What is the Linux audit daemon, and how do you configure it?
6. Explain the concept of cgroups in Linux and their use in resource management.
7. How would you manage high availability (HA) clusters in Linux?
8. How does Linux handle file system integrity, and how do you verify it?
9. How do you configure Linux for multi-user environments?
10. What are Linux containers (LXC), and how do you use them?

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Linux Troubleshooting

1. How would you troubleshoot disk space issues in Linux?
2. How do you debug kernel panic in Linux?
3. How do you resolve boot issues in Linux?
4. What are common Linux performance bottlenecks, and how do you address them?
5. How do you analyze system logs to troubleshoot issues in Linux?
6. How do you recover from accidental file deletion in Linux?
7. What is the significance of dmesg in Linux?
8. How do you troubleshoot network connectivity issues in Linux?
9. How do you resolve issues related to slow application performance in Linux?
10. How do you resolve issues with user permissions in Linux?

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Linux Security

1. How do you configure firewalls in Linux using iptables?
2. How do you harden a Linux server for production use?
3. How do you set up SELinux policies on Linux?
4. How do you manage user privileges in Linux?
5. What is sudoers file, and how do you configure it?
6. How would you protect a Linux server from brute-force attacks?
7. How do you configure Linux for secure remote access using SSH?
8. How do you audit user access and changes in Linux?
9. How do you configure firewalld in Linux for effective network security?
10. How do you implement mandatory access control (MAC) in Linux?

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