my($host,$os,$nproc,$load,$memtot,$memuse,$swapto) = (
    $_ =~ /^(\w+)\s+    # host
            (\w+)\s+    # os
            $procrx\s+  # nproc
            $loadrx\s+  # load
            $sizerx\s+  # memtot
            $sizerx\s+  # memuse
            $sizerx     # swapto
            \s*$
          /x
  );
  if(defined $host) {
    print "using regex, host is [$host]\n";
  } else {
    next;
  }