coreutils: output proper error for unrecognized options (#9869)

Co-authored-by: Sylvestre Ledru <sylvestre@debian.org>

Author: ChrisDryden

src/bin/coreutils.rs

@@ -75,6 +75,11 @@ fn main() {
 
         match util {
             "--list" => {
+                // If --help is also present, show usage instead of list
+                if args.any(|arg| arg == "--help" || arg == "-h") {
+                    usage(&utils, binary_as_util);
+                    process::exit(0);
+                }
                 let mut utils: Vec<_> = utils.keys().collect();
                 utils.sort();
                 for util in utils {
@@ -123,6 +128,9 @@ fn main() {
                     }
                     usage(&utils, binary_as_util);
                     process::exit(0);
+                } else if util.starts_with('-') {
+                    // Argument looks like an option but wasn't recognized
+                    validation::unrecognized_option(binary_as_util, &util_os);
                 } else {
                     validation::not_found(&util_os);
                 }

src/common/validation.rs

@@ -29,6 +29,16 @@ pub fn not_found(util: &OsStr) -> ! {
     process::exit(1);
 }
 
+/// Prints an "unrecognized option" error and exits
+pub fn unrecognized_option(binary_name: &str, option: &OsStr) -> ! {
+    eprintln!(
+        "{}: unrecognized option '{}'",
+        binary_name,
+        option.to_string_lossy()
+    );
+    process::exit(1);
+}
+
 /// Sets up localization for a utility with proper error handling
 pub fn setup_localization_or_exit(util_name: &str) {
     let util_name = get_canonical_util_name(util_name);