Ace Your Linux Interviews: Advanced Questions Decoded!

What’s the toughest Linux question you’ve faced in an interview?

Linux interviews often dig deep into real-world scenarios, testing not just your knowledge but also how you think on your feet.

Over the years, I’ve encountered (and asked!) countless Linux interview questions that go beyond the basics.

So, here’s my take on 30 advanced, scenario-based Linux interview questions – with clear and practical answers!

📍How do you troubleshoot a server that is suddenly unresponsive?

1️⃣ Check connectivity: Use ping or ssh.

2️⃣ Switch to the console: If SSH fails, access the server directly via console or IPMI.

3️⃣ Analyze resource usage: Run top, htop, or free to see if the server is under resource pressure.

4️⃣ Check logs: Use journalctl or /var/log/messages for insights.

📍What’s your approach to resolving high disk I/O issues?

1️⃣ Identify processes: Use iotop or iostat to see which process is causing high I/O.

2️⃣ Check file operations: Use lsof or inotify to track specific file reads/writes.

3️⃣ Optimize storage: Consider tuning filesystems (ext4 journaling mode) or using caching layers.

📍How do you recover a corrupted GRUB bootloader?

1️⃣ Boot using a Linux Live CD/USB.

2️⃣ Mount the root partition:

mount /dev/sdX1 /mnt

3️⃣ Reinstall GRUB:

grub-install – – root-directory=/mnt /dev/sdX

update-grub

📍How do you find which process is using a specific port?

Use the command:

sudo netstat -tulnp | grep :<port_number>

Or, with ss:

ss -tulwn | grep :<port_number>

📍How do you troubleshoot high CPU usage by a single process?

1️⃣ Identify the process:

top -p <PID>

2️⃣ Trace system calls:

strace -p <PID>

3️⃣ Debug further with perf or gdb.

📍Explain how you’d debug a DNS resolution issue.