diff --git a/examples/syncat.go b/examples/syncat.go
index fffdf2f..c9a7c33 100644
--- a/examples/syncat.go
+++ b/examples/syncat.go
@@ -12,6 +12,11 @@ import (
 )
 
 func main() {
+	if len(os.Args) <= 1 {
+		fmt.Println("No input file")
+		return
+	}
+
 	var defs []*highlight.Def
 	gopath := os.Getenv("GOPATH")
 	files, _ := ioutil.ReadDir(gopath + "/src/github.com/zyedidia/highlight/syntax_files")