diff --git a/nsdecode.go b/nsdecode.go
index fd6f04e..6be5c9a 100644
--- a/nsdecode.go
+++ b/nsdecode.go
@@ -49,6 +49,13 @@ func main() {
 
 	flag.Parse()
 
+	// Check if there is input from stdin
+	info, _ := os.Stdin.Stat()
+	if (info.Mode() & os.ModeCharDevice) != 0 {
+		flag.Usage()
+		os.Exit(1)
+	}
+
 	// Read all input from stdin
 	reader := bufio.NewReader(os.Stdin)
 	inputBytes, _ := io.ReadAll(reader)
diff --git a/nsencode.go b/nsencode.go
index 359b36a..531c375 100644
--- a/nsencode.go
+++ b/nsencode.go
@@ -99,6 +99,13 @@ func main() {
 
 	flag.Parse()
 
+	// Check if there is input from stdin
+	info, _ := os.Stdin.Stat()
+	if (info.Mode() & os.ModeCharDevice) != 0 {
+		flag.Usage()
+		os.Exit(1)
+	}
+
 	// Read input from stdin
 	reader := bufio.NewReader(os.Stdin)
 	input, _ := reader.ReadString('\n')