LFCS Essential Commands Practice Question
A user reports that a script fails with 'Permission denied' when executed. The script has permissions -rw-r--r-- and is owned by the user. Which command should the user run to make the script executable for the owner only?
⚠ Common exam trap
Test-takers frequently confuse the setuid bit (`u+s`) with the execute bit (`u+x`), or assume that `chmod +x` is equivalent to `chmod u+x`, when in fact the former grants execute to all users, which is not what the question asks.
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
✓
chmod u+x script.sh
The script currently has permissions `-rw-r--r--`, meaning the owner has read and write but not execute permission. The `chmod u+x` command adds the execute permission for the owner only, which is exactly what the user needs to run the script without affecting group or others.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
chmod u+s script.sh
Why it's wrong here
Sets the setuid bit, not execute.
- ✓
chmod u+x script.sh
Why this is correct
Adds execute permission for the owner only.
- ✗
chown :users script.sh
Why it's wrong here
Changes group ownership, not permissions.
- ✗
chmod +x script.sh
Why it's wrong here
Adds execute for all users, not just owner.
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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.