add more help text

cmd/convergents.go

@@ -49,9 +49,14 @@ func convergents(cmd *cobra.Command, args []string) {
 var convergentsCmd = &cobra.Command{
 	Use:   "convergents N N [N ...]",
 	Short: "Compute convergents of a periodic continued fraction",
-	Long:  `Compute convergents of a periodic continued fraction.`,
-	Args:  cobra.MinimumNArgs(2),
-	Run:   convergents,
+	Long: `Compute convergents of a periodic continued fraction.
+
+The first number given is the integer part. The following numbers give the repetend of the continued fraction.
+
+This will output convergents infinitely. Try piping to head to only output a certain number of convergents, like this:
+mathtools convergents 3 2 6 | head -n 5`,
+	Args: cobra.MinimumNArgs(2),
+	Run:  convergents,
 }
 
 func init() {