Quick Answer
The answer is the `id` command. This is correct because `id` displays the current user's effective user ID (UID), real and effective group ID (GID), and all supplementary group memberships, giving a complete picture of identity and access rights in Linux. On the CompTIA Linux+ XK0-005 exam, this tests your understanding of how Linux determines file access and process permissions, often appearing in questions about privilege escalation or troubleshooting permission denied errors. A common trap is confusing `id` with `whoami` or `groups`—`whoami` only shows the effective username, not the UID or group details, while `groups` lists only group names without numeric IDs. For a quick memory tip: think of `id` as your Linux identity card—it shows everything about who you are and what groups you belong to, all in one command.
This XK0-005 practice question tests your understanding of security. 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.
Which command can be used to display the current user's effective user ID and group memberships?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
id
Displays UID, GID, and supplementary groups.
who
Why wrong: Shows who is logged in, not user details.
groups
Why wrong: Lists group memberships for a user but not the UID.
whoami
Why wrong: Displays the current username only.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
id
The `id` command displays the current user's real and effective user ID (UID), group ID (GID), and supplementary group memberships. It provides a comprehensive view of identity and group associations, which is essential for understanding access rights in Linux security contexts.
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.
id
Why this is correct
Displays UID, GID, and supplementary groups.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
who
Why it's wrong here
Shows who is logged in, not user details.
groups
Why it's wrong here
Lists group memberships for a user but not the UID.
whoami
Why it's wrong here
Displays the current username only.
Common exam traps
CompTIA often tests the distinction between `whoami` (which shows only the effective username) and `id` (which shows both the effective user ID and group memberships), leading candidates to choose `whoami` when the question asks for the effective user ID and group memberships together.
Trap categories for this question
Command / output trap
Shows who is logged in, not user details.
Detailed technical explanation
The `id` command reads from the `/proc/self/status` file and the kernel's credential structures to report real, effective, and saved set-user-ID values. In a real-world scenario, after using `su` or `sudo`, `id` reveals whether the effective UID changed (e.g., from 1000 to 0 for root), while `whoami` would still show the original user if only the real UID changed, making `id` critical for debugging privilege escalation issues.
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.
Security — study guide chapter
Learn the concepts, then practise the questions
Security practice questions
Targeted practice on this topic area only
All XK0-005 questions
510 questions across all exam domains
CompTIA Linux+ XK0-005 study guide
Full concept coverage aligned to exam objectives
XK0-005 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise XK0-005 questions linked to Security.
Practise XK0-005 questions linked to Troubleshooting.
Practise XK0-005 questions linked to Scripting, Containers and Automation.
Practise XK0-005 questions linked to System Management.
Practise XK0-005 questions linked to XK0-005 fundamentals.
Practise XK0-005 questions linked to XK0-005 scenario.
Practise XK0-005 questions linked to XK0-005 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Security — This question tests Security — Read the scenario before looking for a memorised answer..
The correct answer is: id — The `id` command displays the current user's real and effective user ID (UID), group ID (GID), and supplementary group memberships. It provides a comprehensive view of identity and group associations, which is essential for understanding access rights in Linux security contexts.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.