CheckPIDFile checks that the process PID file exists and is readable.

CreatePIDFile checks that the instance PID file is absent or deprecated and creates a new one.

GetPIDFromFile returns PID from the PIDFile.

IsProcessAlive checks if the process is alive.

KillProcessGroup kills a process group using a PID from the pid file as a process group id.

ProcessStatus returns the status of the process.

QuitProcess quits the process by pidFile.

StopProcess stops the process by pidFile.