func explain(w io.Writer, cmd Command) {
	fmt.Fprintf(w, "%s", cmd.Usage())
	subflags := flag.NewFlagSet(cmd.Name(), flag.PanicOnError)
	subflags.SetOutput(w)
	cmd.SetFlags(subflags)
	subflags.PrintDefaults()
}
func explain(w io.Writer, cmd Command) {
	fmt.Fprintf(w, "%s", cmd.Usage())
	subflags := flag.NewFlagSet(cmd.Name(), flag.PanicOnError)
	subflags.SetOutput(w)
	cmd.SetFlags(subflags)
	subflags.PrintDefaults()
}
func explain ( w io . Writer , cmd Command ) { fmt . Fprintf ( w , " " , cmd . Usage ( ) ) subflags := flag . NewFlagSet ( cmd . Name ( ) , flag . PanicOnError ) subflags . SetOutput ( w ) cmd . SetFlags ( subflags ) subflags . PrintDefaults ( ) }
// explainCmd prints a brief description of a single command.
explainCmd prints a brief description of a single command .