Question 366 of 537
Manage users and groupshardMultiple ChoiceObjective-mapped

Use the id Command to Check Current Effective Group Membership After Adding to a Group

This EX200 practice question tests your understanding of manage users and groups. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.

After being added to a new supplementary group with usermod -aG, a user logs out and back in but still cannot access files owned by that group. Which command should the user run to verify current effective group membership?

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.

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

id

The `id` command without arguments displays the real and effective user and group IDs, including all supplementary group memberships. After a user is added to a new group with `usermod -aG`, the change takes effect only in new login sessions; running `id` confirms whether the current shell has actually inherited the new group. Option A (`newgrp -c 'groups'`) is incorrect because `newgrp` is used to change the real group ID, not to display groups, and the `-c` option is not standard. Option C (`groups $(whoami)`) may show cached or database-level information rather than the kernel-level group list that `id` reliably reports. Option D (`usermod -g`) is incorrect because `usermod` modifies user account settings and requires superuser privileges; it does not display group membership.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • newgrp -c 'groups'

    Why it's wrong here

    The `newgrp` command is used to log in with a different group ID, not to display group membership. The `-c` option is not standard and the command as written is invalid.

  • id

    Why this is correct

    The `id` command without arguments displays the real and effective user and group IDs, including all supplementary groups. It reliably shows the kernel-level group list for the current shell.

    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.

  • groups $(whoami)

    Why it's wrong here

    The `groups $(whoami)` command may show cached or database-level information from the group database, not necessarily the groups currently active in the shell's session. The `id` command is more reliable.

  • usermod -g

    Why it's wrong here

    The `usermod -g` command is used to change a user's primary group, not to display group membership. It also requires superuser privileges.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The common pitfall is that after being added to a supplementary group with `usermod -aG`, the change only applies to new login sessions. Even after logging out and back in, some candidates mistakenly believe they must run a command like `newgrp` to 'activate' the group. However, `id` reliably shows the current group membership. Option A (`newgrp -c 'groups'`) is incorrect because `newgrp` is used to change the real group ID for a new shell, not to display current groups. Option C (`groups $(whoami)`) is similar to `id` but less standard; `id` is the recommended command for this verification.

Trap categories for this question

  • Command / output trap

    The `newgrp` command is used to log in with a different group ID, not to display group membership. The `-c` option is not standard and the command as written is invalid.

Detailed technical explanation

How to think about this question

When a user logs in, the `login` process reads `/etc/group` and sets the supplementary group list for the session via the `initgroups()` system call. The `id` command calls `getgroups()` to retrieve the current process's supplementary group list from the kernel, which is why it accurately reflects the groups available to the shell. A common real-world scenario is when a user is added to a group like `docker` or `wheel`; running `id` immediately after logging out and back in confirms the group is active, whereas `groups` may sometimes show stale data if the shell's group cache is not updated.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this EX200 question test?

Manage users and groups — This question tests Manage users and groups — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: id — The `id` command without arguments displays the real and effective user and group IDs, including all supplementary group memberships. After a user is added to a new group with `usermod -aG`, the change takes effect only in new login sessions; running `id` confirms whether the current shell has actually inherited the new group. Option A (`newgrp -c 'groups'`) is incorrect because `newgrp` is used to change the real group ID, not to display groups, and the `-c` option is not standard. Option C (`groups $(whoami)`) may show cached or database-level information rather than the kernel-level group list that `id` reliably reports. Option D (`usermod -g`) is incorrect because `usermod` modifies user account settings and requires superuser privileges; it does not display group membership.

What should I do if I get this EX200 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Are there clue words in this question I should notice?

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.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 24, 2026

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This EX200 practice question is part of Courseiva's free Red Hat 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 EX200 exam.