nohup works correctly on Linux.

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)