LFCS Octal permission notation Practice Question
A user wants to set the permissions of a file to 'rwxr-xr--'. Which octal permission value should they use with chmod?
⚠ Common exam trap
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.
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.
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.
- ✗
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.
Go deeper
Related to this question
About these practice questions
Courseiva writes every LFCS question from scratch — 507 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.