# Assuming $sbFQDN is "host.subdomain.domain.edu", then
#   $sbHost = host.subdomain.domain.edu
#   $sbSubdomain = subdomain.domain.edu
#   $sbDomain = domain.edu
#   $sub = subdomain
#   $host = host
# Assuming $sbFQDN is "host.domain.edu", then
#   $sbHost = host.domain.edu
#   $sbSubdomain = domain.edu
#   $sbDomain = domain.edu
#   $sub = ""
#   $host = host
($sbHost, $sbSubdomain, $sbDomain)=
  ($sbFQDN=~/^([^.]+\.((?:[^.]+\.)?([^.]+\.[^.]+)))$/);
die "Could not obtain the local domain from hostname '$sbFQDN'\n"
	unless $sbDomain;
$sbSubdomain=$sbDomain unless $sbSubdomain;
($sub=$sbSubdomain)=~s/\.?$sbDomain$//;
($host=$sbHost)=~s/\.?$sbSubdomain//;