- A
groupdel groupname
Why wrong: Deletes a group entirely; does not change a user's primary group.
- B
groupmod -g newGID groupname
Changing a group's GID updates the GID in /etc/passwd for users whose primary group is that group.
- C
usermod -g groupname username
-g directly sets primary group for a user.
- D
usermod -G groupname username
Why wrong: -G sets supplementary groups, not primary.
- E
useradd -g groupname username
Why wrong: Creates a new user with specified primary group; does not change existing user's primary group.
Question 445 of 513
LFCS User and Group Management Practice Question
This LFCS practice question tests your understanding of user and group management. 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 TWO commands can change a user's primary group?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"primary"Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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
✓
groupmod -g newGID groupname
Option B is correct because `groupmod -g newGID groupname` changes the GID of a group, and since a user's primary group is identified by GID in `/etc/passwd`, altering the group's GID effectively changes the primary group for all users who have that GID as their primary group. Option C is correct because `usermod -g groupname username` directly modifies the user's primary group entry in `/etc/passwd` to the specified group name or GID.
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.
- ✗
groupdel groupname
Why it's wrong here
Deletes a group entirely; does not change a user's primary group.
- ✓
groupmod -g newGID groupname
Why this is correct
Changing a group's GID updates the GID in /etc/passwd for users whose primary group is that group.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
usermod -g groupname username
Why this is correct
-g directly sets primary group for a user.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
usermod -G groupname username
Why it's wrong here
-G sets supplementary groups, not primary.
- ✗
useradd -g groupname username
Why it's wrong here
Creates a new user with specified primary group; does not change existing user's primary group.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse `-g` (primary group) with `-G` (supplementary groups) in `usermod`, or assume `groupmod -g` only changes the group name without affecting user primary group associations.
Detailed technical explanation
How to think about this question
The primary group is stored as a GID in the fourth field of `/etc/passwd`, while supplementary groups are stored in `/etc/group`. When you use `usermod -g`, it updates the GID in `/etc/passwd` directly, whereas `groupmod -g` changes the GID in `/etc/group` and automatically updates all files owned by that group (via `chown`-like behavior), but does not update `/etc/passwd` entries—so users with that old GID as primary will still reference the old GID unless manually adjusted. A real-world scenario: if you need to reassign a user to a different department's group, `usermod -g` is the direct approach, while `groupmod -g` is useful when renaming a group's GID across the system.
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
Learn the concepts, then practise the questions
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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: groupmod -g newGID groupname — Option B is correct because `groupmod -g newGID groupname` changes the GID of a group, and since a user's primary group is identified by GID in `/etc/passwd`, altering the group's GID effectively changes the primary group for all users who have that GID as their primary group. Option C is correct because `usermod -g groupname username` directly modifies the user's primary group entry in `/etc/passwd` to the specified group name or GID.
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: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
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