Report error on command parsing

src/calanonsync/calanonsync.go

@@ -1,8 +1,10 @@
 package main
 
 import (
+	"fmt"
 	"github.com/spf13/cobra"
 	"log"
+	"os"
 	"time"
 )
 
@@ -13,7 +15,10 @@ func main() {
 		Run:   runSynchronization,
 	}
 
-	rootCmd.Execute()
+	if err := rootCmd.Execute(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
 }
 
 func runSynchronization(cmd *cobra.Command, args []string) {