This LFCS practice question tests your understanding of essential commands. 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 system administrator wants to kill a process with PID 1234 that is not responding to SIGTERM. Which command will forcefully terminate it?
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.
kill -1 1234
Why wrong: Sends SIGHUP, which may not terminate the process.
kill -15 1234
Why wrong: Sends SIGTERM, which the process may ignore.
kill -SIGTERM 1234
Why wrong: Same as kill -15, may be ignored.
kill -9 1234
Sends SIGKILL, forcing termination.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
kill -9 1234
Option D is correct because kill -9 (SIGKILL) sends signal 9, which cannot be caught, blocked, or ignored by the process. Unlike SIGTERM (signal 15), SIGKILL forces the kernel to immediately terminate the process without allowing it to clean up, making it the appropriate choice when a process is unresponsive to SIGTERM.
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.
kill -1 1234
Why it's wrong here
Sends SIGHUP, which may not terminate the process.
kill -15 1234
Why it's wrong here
Sends SIGTERM, which the process may ignore.
kill -SIGTERM 1234
Why it's wrong here
Same as kill -15, may be ignored.
kill -9 1234
Why this is correct
Sends SIGKILL, forcing termination.
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.
Common exam traps
The trap here is that candidates often confuse signal numbers or assume that SIGTERM (signal 15) is always sufficient, not realizing that a process can mask or ignore it, while SIGKILL (signal 9) is the only signal that cannot be handled.
Detailed technical explanation
Under the hood, signals are delivered by the kernel to processes via the process's signal disposition table. SIGKILL (signal 9) bypasses this table entirely and forces the kernel to remove the process from the task list, releasing all resources. A real-world scenario is when a zombie or stuck process holds a file lock or port; SIGKILL is the only way to reclaim those resources without a reboot.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Essential Commands — This question tests Essential Commands — Read the scenario before looking for a memorised answer..
The correct answer is: kill -9 1234 — Option D is correct because kill -9 (SIGKILL) sends signal 9, which cannot be caught, blocked, or ignored by the process. Unlike SIGTERM (signal 15), SIGKILL forces the kernel to immediately terminate the process without allowing it to clean up, making it the appropriate choice when a process is unresponsive to SIGTERM.
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". 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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