XK0-006 Troubleshooting Practice Question
A system is experiencing boot failures. The administrator wants to view kernel messages from the current boot to diagnose the issue. Which two commands can be used to see these messages? (Choose two.)
⚠ Common exam trap
Many exam-takers confuse `dmesg` with `cat /proc/kmsg` or think `boot.log` contains kernel messages, when in fact `dmesg` and `journalctl -k` are the standard tools for viewing kernel ring buffer output from the current boot.
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
✓
journalctl -k
`journalctl -k` displays kernel messages from the current boot by querying the systemd journal, which logs kernel ring buffer messages persistently. `dmesg` reads the kernel ring buffer directly and shows messages from the current boot cycle. Both commands provide the kernel diagnostic output needed to troubleshoot boot failures.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
journalctl -k
Why this is correct
journalctl -k shows kernel messages from the journal.
- ✗
cat /proc/kmsg
Why it's wrong here
/proc/kmsg requires root and is not recommended.
- ✗
tail -f /var/log/boot.log
Why it's wrong here
boot.log contains some messages but not the kernel ring buffer.
- ✓
dmesg
Why this is correct
dmesg displays kernel ring buffer messages.
- ✗
vmstat -f
Why it's wrong here
vmstat -f shows fork statistics.
Go deeper
Related to this question
Learn chapter
Process Management and System Monitoring
Key term
Output
In IT service management, output is the result or deliverable produced by a process, system, or component, such as data, reports, or services delivered to a customer.
Key term
Kernel
The kernel is the core program of an operating system that manages hardware resources and provides essential services for all other software to run.
About these practice questions
One of 979 original XK0-006 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.