fix: handle missing histfile correctly

main.go

@@ -53,11 +53,14 @@ func main() {
 	var history []string
 	b, err := ioutil.ReadFile(histfile)
 	if err != nil {
+		if !os.IsNotExist(err) {
 			log.Fatalf("Failure reading history file: %s", err)
 		}
+	} else {
 		if err := json.Unmarshal(b, &history); err != nil {
 			log.Fatalf("Failure parsing history: %s", err)
 		}
+	}
 
 	if *asDemon {
 		persist := !*noPersist