diff --git a/src/main.rs b/src/main.rs
index ae4a3a5..198b8e0 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -33,27 +33,20 @@ fn server_properties() -> HashMap<String, String> {
 
 #[tokio::main]
 async fn main() -> Result<()> {
-    /* 
-    let args: Vec<String> = env::args().collect();
-    let op_format: &str = if args.len() == 1 || args[1] == "j" {
-        "j" // Default value, json format
-    } else if args[1] == "p" {
-        "p" // Plain format
-    } else if args[1] == "r" {
-        "r" // rson format
-    } else {
-        "j"
-    }; */
-
     let args: optparse::Cli = argh::from_env();
     let op_format = match args.format {
-        Some(value) => value.clone(),  // Cloning the owned String
-        None => "j".to_string(),       // Using the default value as a String
+        Some(value) => value.clone(),
+        None => "j".to_string(),
     };
-    
-    let verbose = args.verbose;
 
-    //let verbose: bool = (args.len() > 2) && (args[2] == "v");
+    if !["r", "j", "p"].contains(&op_format.as_str()) {
+        return Err(zbus::Error::from(std::io::Error::new(
+            std::io::ErrorKind::InvalidInput,
+            "Invalid output format",
+        )));
+    }
+
+    let verbose = args.verbose;
 
     let connection = Connection::session().await?;
     connection
@@ -85,9 +78,6 @@ async fn main() -> Result<()> {
                             println!("GetAll request received for interface: {interface_name}");
                         }
                     } else {
-                        if verbose {
-                            println!("Unknown interface requested: {interface_name}");
-                        }
                         // Reply with an error
                         connection
                             .reply_error(
@@ -96,6 +86,9 @@ async fn main() -> Result<()> {
                                 &"Unknown interface".to_string(),
                             )
                             .await?;
+                        if verbose {
+                            println!("Unknown interface requested: {interface_name}");
+                        }
                     }
                 }
                 "GetServerInformation" => {
diff --git a/src/optparse.rs b/src/optparse.rs
index f3ed7a1..e2a4d67 100644
--- a/src/optparse.rs
+++ b/src/optparse.rs
@@ -3,11 +3,11 @@ use argh::FromArgs;
 #[derive(FromArgs)]
 /// Print desktop notifications
 pub struct Cli {
-    /// select output format: j(json), r(rson), p(plain)
+    /// select output format: r(rson), j(json, default), p(plain)
     #[argh(option, short = 'f')]
     pub format: Option<String>,
 
     /// verbose mode
     #[argh(switch, short = 'v')]
     pub verbose: bool,
-}
\ No newline at end of file
+}