LFCS Essential Commands Practice Question
Exhibit
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1234 99.5 0.2 12345 6789 pts/0 R 10:00 45:00 process_hog
Refer to the exhibit. The output of 'ps aux' shows a process named 'process_hog' with PID 1234 consuming 99.5% CPU. The process is stuck in an infinite loop and does not respond to SIGTERM. Which signal should be used to forcefully terminate it?
⚠ Common exam trap
In LFCS, the key distinction is between termination signals (SIGTERM, SIGKILL) and stop signals (SIGSTOP). SIGTERM allows graceful shutdown, but if ignored, SIGKILL is the only way to force termination. Some candidates incorrectly use SIGSTOP (pause) or confuse SIGTERM with a guaranteed kill.
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
✓
kill -9 1234
SIGKILL (signal 9) cannot be caught, blocked, or ignored by a process, making it the only reliable way to terminate a process that is stuck in an infinite loop and unresponsive to SIGTERM. Since the process does not respond to SIGTERM (signal 15), a forceful kill with kill -9 is necessary.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
kill -2 1234
Why it's wrong here
SIGINT is for interactive processes and is likely to be ignored as well.
- ✓
kill -9 1234
Why this is correct
SIGKILL is the ultimate signal that forcefully terminates the process.
- ✗
kill -15 1234
Why it's wrong here
SIGTERM was already tried and ignored; it would not work.
- ✗
kill -19 1234
Why it's wrong here
SIGSTOP suspends the process; it does not terminate it.
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Written by Johnson Ajibi, MSc IT Security
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