This LFCS practice question tests your understanding of service configuration. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 service that was once enabled is now failing to start. The administrator wants to immediately disable it to prevent boot delays. Which command sequence is correct?
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.
Clue: "immediately / without restart"
Why it matters: Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.
systemctl disable service ; systemctl stop service
Why wrong: Disable then stop, but if disable fails, stop may not run.
systemctl stop service && systemctl disable service
Why wrong: Correct but not the most efficient.
systemctl disable --now service
Stops and disables immediately.
systemctl mask service
Why wrong: Masking prevents any start, but does not stop if already running.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
systemctl disable --now service
Option C is correct because `systemctl disable --now service` both stops the service immediately and disables it from starting at boot in a single atomic command. This is the most efficient way to prevent boot delays caused by a failing service, as it combines the stop and disable actions without relying on shell operators that could fail if the first command exits with a non-zero status.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
systemctl disable service ; systemctl stop service
Why it's wrong here
Disable then stop, but if disable fails, stop may not run.
systemctl stop service && systemctl disable service
Why it's wrong here
Correct but not the most efficient.
systemctl disable --now service
Why this is correct
Stops and disables immediately.
Clue confirmation
The clue words "which command", "immediately / without restart" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
systemctl mask service
Why it's wrong here
Masking prevents any start, but does not stop if already running.
Common exam traps
The trap here is that candidates often choose Option B because they think stopping the service first is safer, but they overlook that the `&&` operator will skip the disable if the stop fails, leaving the service enabled and potentially causing boot delays, whereas `systemctl disable --now` handles both actions reliably regardless of the stop command's exit status.
Detailed technical explanation
The `--now` flag in `systemctl disable --now` is a shortcut that executes both `systemctl stop` and `systemctl disable` in one operation, ensuring the service is stopped before being disabled. Under the hood, `systemctl disable` removes the symlinks from the systemd unit configuration directories (e.g., /etc/systemd/system/multi-user.target.wants/), preventing the service from starting at boot, while `systemctl stop` sends a SIGTERM to the service's control group. In real-world scenarios, a failing service might hang during stop, so using `--now` ensures the disable action is not blocked by a failed stop command, as the systemd daemon handles both actions atomically.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A network engineer segments a warehouse floor into three subnets: 20 scanners, 5 printers, and 2 management hosts. Picking the wrong mask wastes addresses or leaves too few usable hosts. Exam questions test whether you can apply CIDR notation, calculate block size, and identify the correct usable-host range for a given prefix.
What to study next
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FAQ
Service Configuration — This question tests Service Configuration — Read the scenario before looking for a memorised answer..
The correct answer is: systemctl disable --now service — Option C is correct because `systemctl disable --now service` both stops the service immediately and disables it from starting at boot in a single atomic command. This is the most efficient way to prevent boot delays caused by a failing service, as it combines the stop and disable actions without relying on shell operators that could fail if the first command exits with a non-zero status.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "which command", "immediately / without restart". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 2026
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.
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