LFCS Essential Commands Practice Question
A system administrator wants to display a list of all currently running processes with their parent process IDs. Which command is most appropriate?
⚠ Common exam trap
Test-takers frequently confuse 'pstree' (which shows parent-child relationships visually) with 'ps -ef' (which lists numeric PPIDs), or assume 'top' is suitable for a static list, when the question specifically asks for a list with parent process IDs, not a tree or dynamic view.
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
✓
ps -ef
(ps -ef) is correct because the 'ps' command with the '-e' flag displays all processes, and the '-f' flag provides a full-format listing that includes the PPID (parent process ID) in the output. This directly meets the requirement to list all currently running processes with their parent process IDs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
pstree
Why it's wrong here
Shows process tree but not a simple list with PPIDs.
- ✗
jobs
Why it's wrong here
Displays shell jobs, not all processes.
- ✗
top
Why it's wrong here
Interactive process viewer; does not show PPID by default.
- ✓
ps -ef
Why this is correct
Shows all processes with parent PID in the PPID column.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.