killpid

Killpid is a command-line utility used to terminate a running process by its process identifier (PID). It sends a termination signal to the target process via the operating system's process-management facilities. Killpid is commonly employed to stop unresponsive or misbehaving processes and to support automated shutdowns in scripts.

By default it sends a gentle termination request (typically SIGTERM on Unix-like systems). Users can specify stronger signals (such as SIGKILL) to force termination. The exact signals and behavior depend on the platform and the tool's implementation.

Typical usage consists of providing a PID and optional flags to select the signal, wait for completion, or suppress output. Examples: killpid 1234; killpid -s SIGTERM 1234; killpid -s SIGKILL 5678.

Limitations include the requirement for sufficient privileges to terminate another user's process and potential failure to terminate system-critical processes. If the PID does not exist, the tool reports an error or exit status indicating "no such process."

Relation to other tools: killpid is conceptually similar to kill, pkill, and killall. In many environments, it can be implemented as a wrapper around standard system calls or signals, or as part of a larger process-management toolkit.

See also: kill, pkill, killall, posix_kill, signal.