replace log.Fatal with cobra.CheckErr

cmd/primitiveRoot.go

@@ -18,7 +18,6 @@ package cmd
 
 import (
 	"fmt"
-	"log"
 	"math/big"
 
 	"github.com/spf13/cobra"
@@ -45,7 +44,7 @@ func count(tpf []string) map[string]*big.Int {
 func primitiveRoot(cmd *cobra.Command, args []string) {
 	m, ok := new(big.Int).SetString(modulus, 10)
 	if !ok {
-		log.Fatal("invalid input " + modulus)
+		cobra.CheckErr("invalid input " + modulus)
 	}
 
 	factors := count(tpf)
@@ -55,12 +54,12 @@ func primitiveRoot(cmd *cobra.Command, args []string) {
 	if len(factors) == 0 {
 		root, err = lib.PrimitiveRoot(m)
 		if err != nil {
-			log.Fatal(err)
+			cobra.CheckErr(err)
 		}
 	} else {
 		root, err = lib.PrimitiveRootFast(m, factors)
 		if err != nil {
-			log.Fatal(err)
+			cobra.CheckErr(err)
 		}
 	}