Unix Signal Handling

Discussions center on Unix/Linux signals like SIGKILL, SIGTERM, SIGINT, and SIGQUIT, including best practices for process termination, handling interruptions during syscalls, and alternatives like signalfd or PR_SET_PDEATHSIG.

📉 Falling 0.4x DevOps & Infrastructure
3,006
Comments
19
Years Active
5
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#7275
Topic ID

Activity Over Time

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Keywords

CPU catern.com EOF AIX UNIX SIGTTOU SIGABRT SIGHUP CWD SIGTERM signal handler kill signals processes process unix ctrl command caught

Sample Comments

peterwwillis Jan 9, 2020 View on HN

I am upset that they're using signal 9 instead of 15.

baudaux Oct 19, 2023 View on HN

There are being implemented. There is a limitation about signal handling, it can interrupt a process during a sys call

stvltvs Oct 23, 2023 View on HN

Avoiding SIGKILL is probably a good call.

Quarrel Jun 21, 2025 View on HN

I'm more worried that there might be lots of devs that can't send a sigint!

vonuebelgarten Dec 30, 2011 View on HN

Because your signal handler may get interrupted by another signal.

drzaiusapelord Mar 31, 2015 View on HN

Doesn't all sigint? We do sigint for a reason.

omribahumi Nov 11, 2016 View on HN

Another signal that can't be caught is SIGSTOP

ad_hominem Dec 16, 2014 View on HN

SIGUSR1 is often caught by applications for their own IPC. SIGQUIT would probably be a safer one to send, but that can also be caught and repurposed. Sending other signal types would definitely have to be opt-in to prevent unintended side effects.

eru Jan 28, 2014 View on HN

SIGUSER is quite common for that. Or SIGHUP.

amalcon Sep 28, 2011 View on HN

Doing this is more-or-less like calling a signal handler directly in a UNIX program: you're not likely to get the result you want.