print once when unknown algo

src/main.rs

@@ -75,7 +75,10 @@ fn main() -> XResult<()> {
                 },
                 None => match the_algo.as_str() {
                     "SM3" => println!("{}  - {} ({})", hex::encode(Sm3Hash::new(&read_file_full(the_fn)?).get_hash()), the_fn, the_algo),
-                    _ => print_message(MessageType::ERROR, &format!("Unknown algorithm: {}", options.algorithm)),
+                    _ => {
+                        print_message(MessageType::ERROR, &format!("Unknown algorithm: {}", options.algorithm));
+                        return Ok(());
+                    },
                 },
             };
         }