Calls names(Host) for all hosts that are specified in the Erlang host file .hosts.erlang, collects the replies, and then evaluates ping(Node) on all those nodes. Returns the list of all nodes that are successfully pinged.
Arg defaults to silent. If Arg == verbose, the function writes information about which nodes it is pinging to stdout.
This function can be useful when a node is started, and the names of the other network nodes are not initially known.
Returns {error, Reason} if host_file() returns {error, Reason}.