powerman is free Unix/Linux software that controls (remotely and in
parallel) switched power distribution units.  It was designed for remote
power control of Linux systems in a data center or cluster environment, but
has been used in other environments such as embedded management appliances,
home automation, and high availability service management.

powerman can be extended to support new devices using an expect-like
scripting language.  It communicates with devices natively using telnet,
raw socket, and serial protocols.  It also can drive virtual power control
devices via a coprocess interface.  The coprocess mechanism has been used
to extend powerman to communicate with devices using other protocols such
as SNMP, IPMI, Insteon, X-10, and VXI-11.

powerman can control equipment connected using any combination of the above
methods and provide unified naming for the equipment and parallel execution
of control actions.