- A
The user did not explicitly start a new login shell after group removal.
Group membership changes require a new login session; logging out and back in should suffice, but if the user only logged out of the desktop and the session manager cached credentials, it might not refresh. The most likely cause is that the user's current shell environment still has cached group membership from the previous session.
- B
The user's primary group is different from the 'developers' group.
Why wrong: Primary group mismatch does not prevent supplementary group access after re-login.
- C
The user is using 'newgrp developers' but is no longer a member.
Why wrong: Using 'newgrp' without being a member will fail, but the issue is that the user hasn't refreshed their session properly.
- D
The 'id' command shows the old group because the user's shell is still running.
Why wrong: 'id' reads from kernel; after re-login, it should show updated groups.
Quick Answer
The answer is that the user did not explicitly start a new login shell after group removal. This is correct because when a user is removed from a supplementary group, the group membership is cached within the current login session’s process tree. Even after logging out and back in, if the user’s display manager or terminal emulator reuses a cached session or does not spawn a true login shell, the old group list persists—it is inherited from the parent process. On the Linux Foundation Certified System Administrator LFCS exam, this tests your understanding of how the kernel manages supplementary group IDs via the `groups` file and the `initgroups()` function, and it often appears as a trap where candidates assume a simple logout is sufficient. A key memory tip: think of group membership as a sticky note on your current shell—only a fresh login shell (using `su -` or `login`) tears it off and reads the updated list.
LFCS User and Group Management Practice Question
This LFCS practice question tests your understanding of user and group management. 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.
A developer was removed from the 'developers' group but still needs to run commands that require membership in that group. The user has logged out and back in, but the issue persists. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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
The user did not explicitly start a new login shell after group removal.
When a user is removed from a supplementary group, the group membership is cached in the user's current login session. Even after logging out and back in, if the user does not explicitly start a new login shell (e.g., by using `su -` or `login`), the old group membership persists because the session's group list is inherited from the parent process. The `newgrp` command or a fresh login shell is required to re-read the group database and update the group list.
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.
- ✓
The user did not explicitly start a new login shell after group removal.
Why this is correct
Group membership changes require a new login session; logging out and back in should suffice, but if the user only logged out of the desktop and the session manager cached credentials, it might not refresh. The most likely cause is that the user's current shell environment still has cached group membership from the previous session.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The user's primary group is different from the 'developers' group.
Why it's wrong here
Primary group mismatch does not prevent supplementary group access after re-login.
- ✗
The user is using 'newgrp developers' but is no longer a member.
Why it's wrong here
Using 'newgrp' without being a member will fail, but the issue is that the user hasn't refreshed their session properly.
- ✗
The 'id' command shows the old group because the user's shell is still running.
Why it's wrong here
'id' reads from kernel; after re-login, it should show updated groups.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume logging out and back in always refreshes group membership, but the LFCS exam tests the nuance that a new login shell (e.g., `su -` or `login`) is required to reinitialize the group list, not just a graphical logout/login.
Trap categories for this question
Command / output trap
'id' reads from kernel; after re-login, it should show updated groups.
Detailed technical explanation
How to think about this question
Under the hood, group membership is stored in the kernel's credential structure for each process, populated at login time via the `initgroups()` call. This call reads `/etc/group` and sets the supplementary group list for the session. Simply logging out and back in may not trigger a new `initgroups()` if the display manager or terminal multiplexer reuses the same session (e.g., via `pam_systemd`). A real-world scenario is when a user is removed from a Docker group; they must run `newgrp docker` or start a fresh login shell to access Docker commands without `sudo`.
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 practitioner preparing for the LFCS 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
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.
- →
User and Group Management — study guide chapter
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FAQ
Questions learners often ask
What does this LFCS question test?
User and Group Management — This question tests User and Group Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The user did not explicitly start a new login shell after group removal. — When a user is removed from a supplementary group, the group membership is cached in the user's current login session. Even after logging out and back in, if the user does not explicitly start a new login shell (e.g., by using `su -` or `login`), the old group membership persists because the session's group list is inherited from the parent process. The `newgrp` command or a fresh login shell is required to re-read the group database and update the group list.
What should I do if I get this LFCS 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
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 11, 2026
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.
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