diff --git a/exec/tdfiglet.js b/exec/tdfiglet.js
index 943ba5c50523f1ed8d99993b971524edf4322b86..10ffb55e0797a33a0fdf0398cf2844ca587c40d8 100644
--- a/exec/tdfiglet.js
+++ b/exec/tdfiglet.js
@@ -78,4 +78,7 @@ for(i = 0; i < argv.length; ++i) {
 if (!fontfile && !tdf.opt.random)
 	usage();
 
+if (!input_string)
+	usage();
+
 tdf.printstr(input_string, fontfile);