PDNS is normally launched by the init.d script but is actually a binary called pdns_server. This file is started by the start and monitor commands to the init.d script. Other commands are implemented using the controlsocket.
The controlsocket is the means to contact a running PDNS daemon, or as we now know, a running pdns_server. Over this sockets, instructions can be sent using the pdns_control program. Like the pdns_server, this program is normally accessed via the init.d script.
To communicate with PDNS over the controlsocket, the pdns_control command is used. The init.d script also calls pdns_control. The syntax is simple: pdns_control command arguments. Currently this is most useful for telling backends to rediscover domains or to force the transmission of notifications. See Section 12.3.
Besides the commands implemented by the init.d script, for which see Section 2.3, the following pdns_control commands are available:
returns the version of a running pdns daemon.