Top Linux Interview Questions: From Basics to Security and Scripting

Part 1: Linux Basics

Question 1: There are 100 image files with URLs http://down.xiaomi.com/img/1.png … http://down.xiaomi.com/img/100.png. Download all images in batch and identify files larger than 500 KB.

Question 2: The file info.txt contains lines like “aa,201”. Sort the file by the numeric second column in descending order.

Question 3: Check whether the current Linux server is listening on port 80; if it is, find the process ID and terminate the process.

Question 4: Use curl or wget to retrieve the HTTP header of a service.

Question 5: Which statements about Linux user accounts are correct? (A‑D options about password storage and verification.)

Question 6: For a RAID array of N disks, which statement is false? (Options about RAID 1, RAID 5, RAID 0 performance and reliability.)

Question 7: List at least three common load‑balancing software and discuss their drawbacks.

Question 8: After running time sleep 2, explain the meaning and difference of the “real”, “user”, and “sys” times.

Question 9: Explain the meanings of last, break, redirect, and permanent in an Nginx rewrite rule.

Question 10: Describe the difference between web cookies and sessions.

Question 11: Compare HTTP 1.0, HTTP 1.1 and list the main changes or advantages of HTTP 2.0.

Part 2: Security

Question 12: List at least three common web security issues, explaining their principles and potential damage.

Question 13: Enumerate common DoS attack types, describing their principles and mitigation methods.

Question 14: If a server is compromised, what steps should a security administrator take?

Part 3: Networking

Question 15: Briefly describe the three‑way handshake process of TCP.

Question 16: Analyze why a system may have many TIME_WAIT sockets and propose at least three optimization suggestions.

Part 4: Python

Question 17: Compare xrange and range in Python.

Question 18: Given two lists A and B, show a fast Python method to obtain their common elements.

Question 19: Twenty servers need to execute echo "123" concurrently, with at most five servers running in parallel. Provide the relevant Python or shell code.