XK0-006 System Management Practice Question
An administrator needs to give a user read and write access to a file without changing the file's group or adding the user to any group. Which method should be used?
⚠ Common exam trap
Many exam-takers confuse chmod's u+rw (which affects the file owner) with granting permissions to a different user; candidates often forget that traditional chmod cannot target arbitrary users, which is precisely why ACLs exist.
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
✓
setfacl -m u:username:rw file
Access Control Lists (ACLs) allow granting permissions to specific users or groups beyond the traditional owner/group/other model. The command 'setfacl -m u:username:rw file' adds a named user entry to the file's ACL, giving that user read and write access without altering the file's group ownership or requiring group membership changes. This is the standard Linux method for per-user granular permissions.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
chown user: file
Why it's wrong here
chown changes file ownership, not access permissions, so it grants the user nothing without also altering ownership. It is used to reassign a file to another owner. Access control lists (setfacl) grant per-user read and write rights without touching group membership.
- ✗
chmod u+rw file
Why it's wrong here
Setting the owner's own rw bits does nothing for a different user; the file has one owner, so this cannot grant access to anyone else. It is tempting because u+rw is the standard way to adjust owner permissions, and it would be correct when the target user already owns the file.
- ✓
setfacl -m u:username:rw file
Why this is correct
Using `setfacl -m u:username:rw file` writes a POSIX access control list entry granting that named user read and write permission, satisfying the stem's constraint of avoiding group changes or group membership edits. Standard Unix mode bits cannot grant per-user rights without altering owner, group or other classes, so ACLs are the only mechanism here.
- ✗
chgrp to user's primary group
Why it's wrong here
Changing the group alters the file's group ownership, which the scenario explicitly forbids, and the user still gains nothing unless already a member. It is tempting because group ownership is a legitimate access-control mechanism, and it would be correct when the user already belongs to the group being assigned.
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Linux Fundamentals and History
Key term
setfacl
setfacl is a Linux/Unix command used to set Access Control Lists on files and directories, providing more detailed permission control beyond the standard owner-group-others model.
Key term
Linux
Linux is an open-source operating system that manages computer hardware and software, widely used in servers, desktops, and embedded systems.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This XK0-006 practice question is part of Courseiva's free CompTIA 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 XK0-006 exam.