The answer is visudo, the only command that should ever be used to safely edit the sudoers file. Visudo locks the file to prevent concurrent edits and, crucially, performs syntax validation before saving—if you introduce a syntax error, it rejects the changes and preserves the original valid file, preventing the exact scenario where users lose sudo access. On the CompTIA Linux+ XK0-005 exam, this question tests your understanding of privilege escalation and system security; a common trap is choosing a standard text editor like vi or nano directly on /etc/sudoers, which bypasses all safety checks. Remember the mnemonic: “visudo validates” — the ‘v’ stands for both ‘vi’ and ‘verify’, ensuring you never break sudo by accident.
XK0-005 Security Practice Question
This XK0-005 practice question tests your understanding of security. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. 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 junior administrator accidentally modified the /etc/sudoers file and now users report not being able to use sudo. Which command should be used to safely edit the sudoers file?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
visudo
The `visudo` command is the correct and safe way to edit the `/etc/sudoers` file because it locks the file against concurrent edits, performs syntax validation before saving, and prevents saving a malformed configuration that could break sudo entirely. This ensures that even if the administrator makes a mistake, the original valid file is preserved, avoiding the exact scenario described where users lose sudo access.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
visudo
Why this is correct
visudo safely edits /etc/sudoers with syntax checking and file locking.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
chmod 400 /etc/sudoers
Why it's wrong here
Changing permissions does not repair syntax errors in sudoers.
✗
echo 'user ALL=(ALL) ALL' >> /etc/sudoers
Why it's wrong here
Redirecting echo appends text without syntax checking, risking further breakage; visudo should be used.
✗
usermod -aG wheel user
Why it's wrong here
Adding user to wheel group grants sudo access but does not fix the broken sudoers file.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think any method that writes to the file (like `echo` or `chmod`) can fix the issue, but only `visudo` provides the syntax validation and locking necessary to safely edit the sudoers file without breaking sudo.
Detailed technical explanation
How to think about this question
Under the hood, `visudo` invokes the default editor (e.g., vi, nano) on a temporary copy of `/etc/sudoers`, and only after the editor exits does it run a syntax check using the `sudoers` plugin's parser. If the syntax is invalid, `visudo` prompts the administrator to fix the error or abort, leaving the original file untouched — a critical safety mechanism because a single syntax error in `/etc/sudoers` can render sudo unusable for all users, including root, until the system is booted into single-user mode for repair.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
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
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the XK0-005 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. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this XK0-005 question in full detail.
Security — This question tests Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: visudo — The `visudo` command is the correct and safe way to edit the `/etc/sudoers` file because it locks the file against concurrent edits, performs syntax validation before saving, and prevents saving a malformed configuration that could break sudo entirely. This ensures that even if the administrator makes a mistake, the original valid file is preserved, avoiding the exact scenario described where users lose sudo access.
What should I do if I get this XK0-005 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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