Top 19 Essential Linux & Sysadmin Interview Questions with Answers

Part 1: Linux Basics

Question 1: How to batch‑download 100 image files from http://down.xiaomi.com/img/1.png … http://down.xiaomi.com/img/100.png and find those larger than 500 KB?

Question 2: Sort the file

info.txt

(format

aa,201

etc.) by the numeric second column in descending order.

Question 3: Check if the Linux server is listening on port 80, obtain its PID, and terminate the process.

Question 4: Retrieve HTTP header information using

curl

or

wget

.

Question 5: Which statements about Linux user accounts are correct?

Question 6: Identify the incorrect statement about RAID configurations.

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

Question 8: Explain the meanings and differences of

real

,

user

, and

sys

times from

time sleep 2

.

Question 9: Meaning of nginx rewrite flags

last

,

break

,

redirect

,

permanent

.

Question 10: Difference between cookies and sessions.

Question 11: Differences between HTTP/1.0 and HTTP/1.1, and main advantages of HTTP/2.

Part 2: Security

Question 12: Common web security issues (at least three) with their principles and impacts.

Question 13: Common DoS attack types, their principles, and mitigation methods.

Question 14: Steps a security manager should take after a server intrusion.

Part 3: Networking

Question 15: Describe the TCP three‑way handshake.

Question 16: Causes of many TIME_WAIT sockets and at least three optimization suggestions.

Part 4: Python

Question 17: Differences between

xrange

and

range

.

Question 18: Quickly obtain common elements of two lists

A

and

B

in Python.

Question 19: Execute

echo "123"

on 20 servers in parallel, limiting concurrency to 5, using Python or shell.