diff --git a/nohup/main.go b/nohup/main.go
index ed4a307..6db12b0 100644
--- a/nohup/main.go
+++ b/nohup/main.go
@@ -52,6 +52,10 @@ func main() {
   flag.Parse()
   args := flag.Args()
 
+  if flag.NArg() == 0 {
+	  log.Fatal("USAGE: nohup cmd [args]")
+  }
+
   output := OpenOutput()
   Exec(args[0], args[1:], output)