Many UNIX system services ("daemons") provide for a mechanism of re-starting themselves. The usual mechanism is through signal
handling. Simply send the "SIGHUP", or "1", signal to the process and it will (assuming it has been written this way) restart itself. To send this signal, use the "kill" command.
kill -1 pid
If the daemon does not
"handle" the signal in this way, it will likely be killed
. In that case, you will need to restart the daemon "by hand".
Some daemons that notably do not
restart themselves include:
DHCP (from ISC)
Most "interactive" processes will terminate when you send the HUP signal.