kill signal
also: signal, SIGKILL, SIGTERM, termination signal
A signal sent to a process to request or force its termination. The most common is SIGKILL (signal 9), which forcefully stops a process, while SIGTERM (signal 15) allows graceful shutdown.
A kill signal is an inter-process communication mechanism that tells a running process to stop. Signals are numbered (like 9 for SIGKILL or 15 for SIGTERM) and can be sent using the kill command or by the kernel itself.
Different signals allow different levels of control: SIGTERM (15) politely asks a process to terminate and clean up resources, while SIGKILL (9) forcefully kills it without warning. Other signals like SIGHUP (1) or SIGUSR1 (10) can trigger custom behavior.
Example: kill -15 1234 sends SIGTERM to process ID 1234, giving it a chance to exit cleanly. If it doesn't respond, kill -9 1234 forces immediate termination.