killSignal

KillSignal is a term used in computing to describe a mechanism that requests termination of a running process, task, or operation. It is commonly realized as signals in Unix-like operating systems, though analogous concepts exist in other environments. The exact meaning and handling of a kill signal depend on the context and the receiving entity’s design.

In Unix and POSIX systems, termination signals are a core part of inter-process communication. The most common signals related to termination are SIGTERM, SIGINT, and SIGKILL. SIGTERM asks a process to terminate gracefully, allowing it to perform cleanup. SIGINT is typically generated by an interrupt from the user, such as pressing Ctrl-C. SIGKILL forces immediate termination with no opportunity for cleanup. Receiving processes can install handlers to intercept or customize responses to these signals; otherwise, the default action is termination.

Sending a kill signal is usually done through the kill system call, invoked by a user-space process with a target process ID. The call can specify different signals; using a signal number or name, one can request normal termination, an interrupt, or an abrupt kill.

In practice, kill signals are central to process management in servers, daemons, and container orchestration. For example, orchestration systems may send SIGTERM to containers to allow orderly shutdown, followed by SIGKILL after a grace period if the container does not terminate.

Safety considerations include avoiding data loss and ensuring proper cleanup. Proper use typically favors graceful termination signals (like SIGTERM) first, reserving forceful signals (like SIGKILL) for unresponsive cases.