kill (command)

In computing, kill is a command that is used in several popular operating systems to send signals to running processes.

In Unix and Unix-like operating systems, kill is a command used to send a signal to a process.

Programs that handle this signal can do useful cleanup operations (such as saving configuration information to a file) before quitting.

Other times, even a process that has a special handler has gone awry in a way that prevents it from properly handling the signal.

The two exceptions SIGKILL and SIGSTOP are only seen by the host system's kernel, providing reliable ways of controlling the execution of processes.

[3] Unix provides security mechanisms to prevent unauthorized users from killing other processes.

Some daemons, including Apache and Sendmail, re-read configuration files upon receiving SIGHUP, so the kill command may be used for this too.

Microsoft Windows XP, Vista and 7 include the command taskkill[5] to terminate processes.