Seonglae ChoIn Linux, various signals (e.g., SIGHUP, SIGUSR1) have a default behavior of "terminating the process if no handler is registered," which can cause large-scale service outages. Therefore, the new pkill feature below only sends signals to processes that have handlers registered for those signals.
Preventing outages with pkill's new --require-handler flag
A safer approach to using signals in production systems, avoiding service outages when signal handlers are removed.
https://chrisdown.name/2025/05/13/safer-signal-sending-with-pkill-require-handler.html
