15 to 30 random questions in 15 to 30 minutes, by the level you choose: permissions, processes, systemd, text tools, scripting, ssh, debugging. After you submit you get your score, your strong and weak topics, and the right answer with an explanation for every question.
Want to revise first? Read the Linux interview questions and answers.
The test covers 13 topics across three levels. Each attempt picks 15 to 30 questions at random, by the level you choose, so every attempt is different.
One question from each level, the way they appear in the test. A new set comes on the 1st of every month. Try it, then open the answer.
Answer: ss -tln. For ss, -t means TCP, -l listening sockets only and -n numbers instead of names; add -p (as root) to see the process. -u -a shows all UDP sockets, ip -s link shows interface counters and ip neigh shows the ARP table.
Answer: journalctl -p err -b. -p filters by syslog priority (err includes crit, alert and emerg) and -b limits output to the current boot; -b -1 shows the previous one. -k is kernel messages, -e jumps to the end and -u expects a unit name.
Answer: Write -1000 to /proc/PID/oom_score_adj, or set OOMScoreAdjust=-1000 in the unit. The OOM killer picks the process with the highest oom_score, and oom_score_adj shifts it from -1000 (never kill) to 1000. systemd sets it with OOMScoreAdjust=. Niceness is CPU only and root processes can be killed too.
Take the full Linux mock test: 15 to 30 questions and 15 to 30 minutes, by level.
A question counts as right only when you pick exactly the right option, or all the right options where it says so; a question left blank counts as wrong. Your score is the share of the test's questions you got right (15 to 30, by level). The result also scores every topic, so you know what to revise before the interview.
Yes. The Linux mock test is free. You need a free CoreHRx Jobs account to start it, so your score and the topics to work on are saved.
It depends on the level: Fresher has 15 questions in 15 minutes, Intermediate has 20 questions in 20 minutes, Experienced has 30 questions in 30 minutes. They are multiple-choice questions picked at random from a larger bank of Linux questions at your level, so every attempt is different.
The questions cover Shell Scripting, Text Processing, Permissions and Ownership, Processes and Signals, Disk and Memory, Networking Commands, Logs and Troubleshooting, File System and Links, systemd Services, Users and Groups, Package Management, Cron and Scheduling, SSH and Remote Access. Your result shows how you did in each topic.
Fresher if you are a student or have less than a year of experience, Intermediate for 1 to 5 years at work, and Experienced for 5 years or more.
Only your best Linux score, and only when it is 60% or more. It shows on the job applications you send on CoreHRx. Lower scores stay private.
Yes, up to 10 tests a day. Each attempt picks questions you have not seen recently first.
