GNU Pies (pronounced "p-yes") is a Program Invocation and Execution Supervisor daemon. This utility starts and controls execution of external programs, called components. Each component is a stand-alone program, which is executed in the foreground. Upon startup, pies reads the list of components from its configuration file, starts them, and remains in the background, controlling their execution. When a component terminates, pies restarts it. Its configuration allows to specify actions other than simple restart, depending on the exit code of the component.