"In part one of this series the basic trusses needed by
the Nagios check_systemhealth script were put together. In part two
the actual checks themselves were coded. In this the third and
final part of the series compulsory checks are added, the main loop
is constructed and the finall full source listing produced.
"For the purposes of this script the compulsory checks are ping
and functioning DNS resolution for the system being checked. These
will have the capability of being overridden at runtime (see the
usage() sub routine for details)."