Quick Answer
The answer is top and ps aux --sort=-%cpu. The top command is the standard tool for monitoring real-time process CPU usage because it provides a continuously updating, dynamic view of all running processes, automatically sorting them by CPU consumption by default. The ps aux --sort=-%cpu command, while technically a snapshot, can be run repeatedly in a loop or with watch to approximate real-time monitoring, making it a valid alternative for identifying high-CPU processes. On the CompTIA Linux+ XK0-005 exam, this question tests your ability to distinguish between tools that offer live updates versus those that require manual repetition—a common trap is assuming ps cannot be used for real-time monitoring at all. Remember that top is the go-to for continuous display, while ps with sorting gives you a clean, one-time list you can refresh. A helpful memory tip: “top is always on top of real-time CPU, but ps can play catch-up with a sort flag.”
This XK0-005 practice question tests your understanding of troubleshooting. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A web server is experiencing high load. The administrator wants to identify the processes consuming the most CPU. Which TWO commands can be used to display real-time process CPU usage?
lsof
Why wrong: Lists open files, not CPU usage.
iostat
Why wrong: Reports I/O statistics, not CPU per process.
vmstat
Why wrong: Reports system-wide CPU stats, not per process.
top
Correct: Real-time process viewer with CPU usage.
ps aux --sort=-%cpu
Correct: Sorts processes by CPU usage in snapshot.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
top
Option D (top) is correct because it provides a real-time, dynamic view of system processes, including CPU usage, and updates continuously by default. Option E (ps aux --sort=-%cpu) is also correct because it lists all processes sorted by CPU usage in descending order, though it is a snapshot rather than continuous; however, the question asks for commands that can be used to display real-time process CPU usage, and ps with the --sort flag can be run repeatedly to approximate real-time monitoring.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
lsof
Why it's wrong here
Lists open files, not CPU usage.
iostat
Why it's wrong here
Reports I/O statistics, not CPU per process.
vmstat
Why it's wrong here
Reports system-wide CPU stats, not per process.
top
Why this is correct
Correct: Real-time process viewer with CPU usage.
Related concept
Read the scenario before looking for a memorised answer.
ps aux --sort=-%cpu
Why this is correct
Correct: Sorts processes by CPU usage in snapshot.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
CompTIA often tests the distinction between system-wide monitoring tools (iostat, vmstat) and per-process tools (top, ps), leading candidates to mistakenly choose iostat or vmstat when the question explicitly asks for processes consuming the most CPU.
Detailed technical explanation
The top command reads /proc/stat and /proc/[pid]/stat files on Linux to compute per-process CPU percentages in real time, updating every 3 seconds by default. The ps command with --sort=-%cpu sorts processes by the %CPU field, which is calculated as the ratio of CPU time used to the elapsed time since the process started; running ps repeatedly (e.g., via watch) can simulate real-time monitoring. In high-load scenarios, administrators often combine top with batch mode (-b) and a specific number of iterations (-n) for logging, or use ps with --forest to visualize process trees.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the XK0-005 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Troubleshooting — study guide chapter
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FAQ
Troubleshooting — This question tests Troubleshooting — Read the scenario before looking for a memorised answer..
The correct answer is: top — Option D (top) is correct because it provides a real-time, dynamic view of system processes, including CPU usage, and updates continuously by default. Option E (ps aux --sort=-%cpu) is also correct because it lists all processes sorted by CPU usage in descending order, though it is a snapshot rather than continuous; however, the question asks for commands that can be used to display real-time process CPU usage, and ps with the --sort flag can be run repeatedly to approximate real-time monitoring.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This XK0-005 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the XK0-005 exam.
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