This LFCS practice question tests your understanding of user and group management. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 team of developers must share files under /opt/project. All developers are members of the 'devteam' group. New files must be automatically assigned to group 'devteam' and be writable by the group. Which umask and setgid configuration should be applied?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Set setgid bit on /opt/project and set umask for developers to 002
Option A is correct: chmod g+s sets the setgid bit so new files inherit the group; umask 002 gives group write permission (files 664, dirs 775). Option B: umask 002 but no setgid means new files will inherit the creator's primary group, not necessarily 'devteam'. Option C: umask 007 removes group permissions entirely. Option D: umask 022 gives group read-only.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Set setgid bit on /opt/project and set umask to 007
Why it's wrong here
umask 007 removes all group permissions (files 660, dirs 770) which denies group write.
✗
Set the sticky bit on /opt/project and umask to 022
Why it's wrong here
Sticky bit affects deletion, not group inheritance; umask 022 gives group read only.
✗
Set umask for developers to 002 only
Why it's wrong here
Without setgid, new files may be owned by the user's primary group, not 'devteam'.
✓
Set setgid bit on /opt/project and set umask for developers to 002
Why this is correct
Setgid ensures group ownership inheritance; umask 002 ensures group write.
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
How this comes up in practice
A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related LFCS subnetting questions on CIDR, address ranges, and subnet selection.
User and Group Management — This question tests User and Group Management — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Set setgid bit on /opt/project and set umask for developers to 002 — Option A is correct: chmod g+s sets the setgid bit so new files inherit the group; umask 002 gives group write permission (files 664, dirs 775). Option B: umask 002 but no setgid means new files will inherit the creator's primary group, not necessarily 'devteam'. Option C: umask 007 removes group permissions entirely. Option D: umask 022 gives group read-only.
What should I do if I get this LFCS question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related LFCS subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
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Question Discussion
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