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LFCS · Question #784
LFCS Question #784: Real Exam Question with Answer & Explanation
The correct answer is D: 027. To achieve default file permissions of -rw-r-----, which is octal 640, an administrator must set the umask to 027 to mask out write permission for the group and all permissions for others.
Submitted by klara.se· Apr 18, 2026User and Group Management
Question
An administrator wants the default permissions for their files to be -rw-r-----. How must the administrator set umask?
Options
- A037
- B640
- C038
- D027
Explanation
To achieve default file permissions of -rw-r-----, which is octal 640, an administrator must set the umask to 027 to mask out write permission for the group and all permissions for others.
Common mistakes.
- A. A umask of 037 would result in file permissions of 630 (rw- -wx ---), which is not the desired -rw-r-----.
- B. 640 represents the desired file permissions, not the umask value; the umask specifies permissions to be removed from the default.
- C. 038 is an invalid octal number because '8' is not a valid octal digit, making it an impossible umask setting.
Concept tested. Linux umask and default file permissions
Reference. https://man7.org/linux/man-pages/man2/umask.2.html
Topics
#umask#File permissions#Default permissions#Access control
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