Binary package “insserv” in ubuntu xenial

boot sequence organizer using LSB init.d script dependency information

 The insserv program is used by the standard SysV-based init system. It
 updates the order of symlinks in /etc/rc?.d/ based on dependencies
 specified by LSB headers in the init.d scripts themselves.
 These declared relations between scripts make it possible to optimize
 the boot sequence for the currently installed set of packages, while
 detecting and rejecting dependency loops.
 Using insserv incorrectly can result in an unbootable system.