diff --git a/identities/generator.go b/identities/generator.go
index 8da4212..275d459 100644
--- a/identities/generator.go
+++ b/identities/generator.go
@@ -3,7 +3,6 @@ package identities
 import (
 	"encoding/json"
 	"errors"
-	"flag"
 	"fmt"
 	"io"
 	"math/rand"
@@ -19,30 +18,28 @@ func MainModule(args map[string]interface{}, out io.Writer) {
 			fmt.Fprintln(out, "Error occurred: ", r)
 		}
 	}()
+	dt_fmt := args["dt_fmt"].(string)
 	minage := args["minage"].(int)
 	maxage := args["maxage"].(int)
-	n := args["n"].(int)
-	dateformat := args["dateformat"].(string)
+	number := args["number"].(int)
 	format := args["format"].(string)
-	filter := args["filter"].(string)
+	fields := args["fields"].(string)
 
-	if minage >= maxage || n <= 0 {
-		flag.PrintDefaults()
+	if minage >= maxage || number <= 0 {
+		panic("'minage' should be less than or equal to 'maxage'")
 	}
-	if filter != "all" {
-		tmp := strings.Split(filter, ",")
+	if fields != "all" {
+		tmp := strings.Split(fields, ",")
 		err := SetFilter(tmp)
 		if err != nil {
-			fmt.Println(err)
-			flag.PrintDefaults()
+			panic(err)
 		}
 	}
 
-	LocalizDate = NewDateFormat(dateformat)
-	people, err := RandomPeople(minage, maxage, n)
+	LocalizDate = NewDateFormat(dt_fmt)
+	people, err := RandomPeople(minage, maxage, number)
 	if err != nil {
-		fmt.Println(err)
-		return
+		panic(err)
 	}
 	tmpArray := strings.Split(format, ",")
 
@@ -60,16 +57,14 @@ func MainModule(args map[string]interface{}, out io.Writer) {
 		case "json":
 			b, err := json.MarshalIndent(&people, "", "\t")
 			if err != nil {
-				fmt.Println("error:", err)
-				return
+				panic(err)
 			}
 			_, _ = out.Write(b)
 			fmt.Fprintln(out)
 		case "csv":
 			err := MarshalCSV(people, out)
 			if err != nil {
-				fmt.Println("error:", err)
-				return
+				panic(err)
 			}
 			fmt.Fprintln(out)
 		default:
diff --git a/main.go b/main.go
index 65e5331..d4fb4f1 100644
--- a/main.go
+++ b/main.go
@@ -9,20 +9,20 @@ import (
 
 var minage = flag.Int("minage", 25, "The minimum age for random people generation. Must be positive and less than maxage.")
 var maxage = flag.Int("maxage", 55, "The maximum age for random people generation. Must be positive and more than minage.")
-var n = flag.Int("n", 1, "The amount of random people to generate. Must be positive.")
-var dateformat = flag.String("dateformat", "eu", "The format of the dates. Supports: 'eu','us','ja'")
+var number = flag.Int("number", 1, "The amount of random people to generate. Must be positive.")
+var dt_fmt = flag.String("dt_fmt", "eu", "The format of the dates. Supports: 'eu','us','ja'")
 var format = flag.String("format", "human", "The comma separated list of formats for the output. Supports: 'json', 'csv', 'human'")
-var filter = flag.String("fields", "all", "The comma separated list of fields to print. Use 'all' to print all of them")
+var fields = flag.String("fields", "all", "The comma separated list of fields to print. Use 'all' to print all of them")
 
 func main() {
 	flag.Parse()
 	args := make(map[string]interface{})
+	args["dt_fmt"] = *dt_fmt
 	args["minage"] = *minage
 	args["maxage"] = *maxage
-	args["n"] = *n
-	args["dateformat"] = *dateformat
+	args["number"] = *number
 	args["format"] = *format
-	args["filter"] = *filter
+	args["fields"] = *fields
 
 	identities.MainModule(args, os.Stdout)
 }