- A
754
Correct. rwx = 7, r-x = 5, r-- = 4, giving 754.
- B
755
Why wrong: Incorrect. 755 gives others execute (r-x), but the required permissions are r-- for others.
- C
644
Why wrong: Incorrect. 644 gives rw-r--r--, missing execute for owner and group.
- D
744
Why wrong: Incorrect. 744 gives rwxr--r--, missing execute for group.
Question 100 of 513
LFCS Octal permission notation Practice Question
This LFCS practice question tests your understanding of essential commands. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. A key principle to apply: octal permission notation. 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 user wants to set the permissions of a file to 'rwxr-xr--'. Which octal permission value should they use with chmod?
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
✓
754
The permissions 'rwxr-xr--' mean that the owner has read, write, and execute (rwx = 7), the group has read and execute (r-x = 5), and others have only read (r-- = 4). Therefore, the correct octal value is 754. Option A is correct. Option B (755) gives others execute, option C (644) gives owner no execute and group no execute, and option D (744) gives group no execute.
Key principle: Octal permission notation
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
754
Why this is correct
Correct. rwx = 7, r-x = 5, r-- = 4, giving 754.
Related concept
Octal permission notation
- ✗
755
Why it's wrong here
Incorrect. 755 gives others execute (r-x), but the required permissions are r-- for others.
- ✗
644
Why it's wrong here
Incorrect. 644 gives rw-r--r--, missing execute for owner and group.
- ✗
744
Why it's wrong here
Incorrect. 744 gives rwxr--r--, missing execute for group.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Candidates often miscompute the octal digits by forgetting that each class (owner, group, others) is calculated independently. Common errors include picking 755 (adding execute for others) or 744 (forgetting group execute). The new option C (644) also shows a mistake where both owner and group execute are omitted.
Detailed technical explanation
How to think about this question
Octal permissions are a compact representation of the 9-bit permission mask in Unix/Linux. Each digit (0-7) maps to a 3-bit set: read (4), write (2), execute (1). The chmod command directly interprets these octal values without needing symbolic mode parsing, making it efficient for scripting. In practice, 754 is common for executable files that should be readable by all but writable only by the owner.
KKey Concepts to Remember
- Octal permission notation
- chmod
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
Octal permission notation
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. Octal permission notation 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.
Review octal permission notation, then practise related LFCS questions on the same topic to reinforce the concept.
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FAQ
Questions learners often ask
What does this LFCS question test?
Essential Commands — This question tests Essential Commands — Octal permission notation.
What is the correct answer to this question?
The correct answer is: 754 — The permissions 'rwxr-xr--' mean that the owner has read, write, and execute (rwx = 7), the group has read and execute (r-x = 5), and others have only read (r-- = 4). Therefore, the correct octal value is 754. Option A is correct. Option B (755) gives others execute, option C (644) gives owner no execute and group no execute, and option D (744) gives group no execute.
What should I do if I get this LFCS question wrong?
Review octal permission notation, then practise related LFCS questions on the same topic to reinforce the concept.
What is the key concept behind this question?
Octal permission notation
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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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