How do you find a running process and stop it? What is the difference between SIGTERM and SIGKILL?
What they are really testing: Whether you handle processes gracefully or just reach for kill -9. The signal difference is the real test: do you understand graceful shutdown vs forced termination.
A real interview question
How do you find a running process and stop it? What is the difference between SIGTERM and SIGKILL?
What most people say
drag me
“I would run kill -9 on the process id to stop it.”
Jumping straight to -9 is the junior tell: it denies the process any cleanup and risks corruption. It also skips SIGTERM entirely, which is what you should try first.
The follow-ups they ask next
A process is stuck and even kill -9 does not remove it. Why?
It is likely in uninterruptible sleep (state D), blocked in a kernel syscall, often on stuck I/O (a hung disk or NFS mount). The fix is the underlying I/O, not the signal.
How do you stop all processes by name at once?
pkill <name> or killall <name>, but be careful with broad name matches; confirm with pgrep first.
What the interviewer is listening for
- Tries SIGTERM before SIGKILL
- Explains why -9 risks corruption
- Knows ps/pgrep/top to find PIDs
What sinks the answer
- Reaches for kill -9 first
- Can't explain the signal difference
- Unaware -9 skips cleanup
If you genuinely do not know
Say this instead of freezing. Reasoning out loud from what you do know beats silence every single time, and a good interviewer is listening for exactly that.
“I find the PID with [ps aux | grep or pgrep], then send [SIGTERM via plain kill] so it [shuts down cleanly]. Only if it ignores that do I use [kill -9 / SIGKILL], which [forces it with no cleanup and risks corruption], so it is a last resort.”
Keep going with linux
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