XK0-006 Services and User Management Practice Question
A user reports that they cannot run the command `sudo` to perform administrative tasks. The administrator checks and finds that the user is not listed in the `/etc/sudoers` file. Which command should the administrator use to safely edit the sudoers file and add the user?
⚠ Common exam trap
The trap here is assuming that any method of editing the sudoers file is acceptable, overlooking the critical safety features of visudo.
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
✓
visudo
Using `visudo` is the correct approach because it provides a safe editing environment with syntax validation and file locking. Directly editing the sudoers file or appending to it can introduce errors that break sudo. Adding a user to a group like sudo is an alternative but does not address the specific need to edit the sudoers file safely.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
echo 'username ALL=(ALL) ALL' >> /etc/sudoers
Why it's wrong here
Appending directly to `/etc/sudoers` with `echo` bypasses all safety mechanisms. It can easily create syntax errors or duplicate entries, and it does not lock the file. This method is dangerous and not recommended; `visudo` should be used instead to ensure the file remains valid.
- ✓
visudo
Why this is correct
`visudo` is the recommended tool for editing the `/etc/sudoers` file because it locks the file to prevent concurrent edits and performs syntax checking before saving. This reduces the risk of introducing errors that could lock out sudo access. It is the safe and standard method for modifying sudoers.
- ✗
usermod -aG sudo username
Why it's wrong here
`usermod -aG sudo username` adds the user to the sudo group, which is a valid way to grant sudo privileges on some distributions (like Ubuntu). However, the question specifies that the user is not listed in `/etc/sudoers`, and the administrator wants to edit that file safely. This command does not edit the sudoers file; it modifies group membership, which may not be the desired approach.
- ✗
nano /etc/sudoers
Why it's wrong here
Editing `/etc/sudoers` directly with a text editor like `nano` bypasses the safety checks provided by `visudo`. If a syntax error is introduced, sudo may become unusable, potentially locking out administrative access. It is strongly discouraged to edit the sudoers file directly without using `visudo`.
Go deeper
Related to this question
Learn chapter
File Permissions and Ownership
Key term
sudo
sudo is a command-line utility in Unix-like operating systems that allows a permitted user to execute a program as another user, typically the superuser (root), based on security policy settings.
Key term
User
A user is any person, system, or device that interacts with an IT service, resource, or identity system, typically authenticated through credentials and authorized to perform specific actions.
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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.