fnping is used (not surprisingly) to `ping' objects to see if they are alive. fnping takes a UOL as its input (see Section 5.2.1 for more information on UOLs).
Usage:
$ fnping UOL $ fnping -f AFileContainingAUOL $ fnping `cat AFileContainingAUOL` $ fnping < AFileContainingAUOL