LFCS Operation of Running Systems Practice Question
A Linux server is experiencing performance issues. You need to identify which processes are consuming the most CPU and memory in real-time. Which two commands can provide this information interactively? (Choose two.)
⚠ Common exam trap
The trap here is assuming that ps aux provides real-time updates, when it only shows a static snapshot at the moment of execution.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
top
top and htop are interactive process viewers that display real-time CPU and memory usage per process. vmstat and iostat provide system-wide statistics but lack per-process detail and interactivity. ps aux gives a static snapshot, not real-time updates. Therefore, top and htop are the correct choices.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
iostat
Why it's wrong here
iostat is used for monitoring system input/output device loading by observing the time devices are active in relation to their average transfer rates. It focuses on disk I/O and does not provide per-process CPU or memory usage. It is not interactive and does not show process-level details.
- ✓
top
Why this is correct
top is an interactive process viewer that displays a real-time list of processes sorted by CPU usage by default. It shows CPU and memory usage per process and updates periodically. It allows interactive commands like sorting by memory (press M) and killing processes. This directly meets the requirement for real-time monitoring of CPU and memory.
- ✗
vmstat
Why it's wrong here
vmstat reports virtual memory statistics, including processes, memory, paging, block I/O, traps, and CPU activity. While it provides system-wide CPU and memory information, it does not show per-process details or allow interactive sorting. It is not an interactive process viewer, so it does not meet the requirement.
- ✓
htop
Why this is correct
htop is an interactive process viewer similar to top but with a more user-friendly interface, color coding, and additional features like horizontal and vertical scrolling. It displays CPU and memory usage per process in real-time and allows sorting and filtering. htop is not always installed by default, but it is a valid command for this purpose.
- ✗
ps aux
Why it's wrong here
ps aux provides a snapshot of current processes with CPU and memory usage, but it is not interactive and does not update in real-time. It shows a static list at the moment of execution. While useful, it does not offer the real-time, interactive monitoring that top and htop provide.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Linux Foundation exam blueprint
This LFCS practice question is part of Courseiva's free Linux Foundation 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 LFCS exam.