add more help text

cmd/totient.go

@@ -63,10 +63,12 @@ func totient(cmd *cobra.Command, args []string) {
 
 // totientCmd represents the totient command
 var totientCmd = &cobra.Command{
-	Use:   "totient",
+	Use:   "totient -n N",
 	Short: "Compute the totient function for all numbers less than n",
-	Long:  `Compute the totient function for all numbers less than n.`,
-	Run:   totient,
+	Long: `Compute the totient function for all numbers less than n.
+
+The totient function phi(n) counts the numbers up to n that are coprime to n.`,
+	Run: totient,
 }
 
 func init() {