mkdir: require argument

src/uu/mkdir/src/mkdir.rs

@@ -127,6 +127,7 @@ pub fn uu_app() -> Command {
             Arg::new(options::DIRS)
                 .action(ArgAction::Append)
                 .num_args(1..)
+                .required(true)
                 .value_parser(ValueParser::os_string())
                 .value_hint(clap::ValueHint::DirPath),
         )

tests/by-util/test_mkdir.rs

@@ -15,6 +15,14 @@ fn test_invalid_arg() {
     new_ucmd!().arg("--definitely-invalid").fails().code_is(1);
 }
 
+#[test]
+fn test_no_arg() {
+    new_ucmd!()
+        .fails()
+        .code_is(1)
+        .stderr_contains("error: the following required arguments were not provided:");
+}
+
 #[test]
 fn test_mkdir_mkdir() {
     new_ucmd!().arg("test_dir").succeeds();