Library/executable for initializing signal handlers, spawning and
 child process, and reaping orphan processes. These are the
 responsibilities that must be fulfilled by the initial process in a
 Unix system, and in particular comes up when running Docker
 containers.
 .
 This library/executable will automatically detect if it is run as some
 process besides PID1 and, if so, use a straightforward exec system
 call instead.