diff --git a/src/main.rs b/src/main.rs
index da8e955..24a1317 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -23,7 +23,13 @@ fn main() -> std::io::Result<()>{
 	.expect("Failed to init the logger");
     
     let args: Vec<String> = env::args().collect();
-    info!("File: {}", &args[1]);
+    let file_path = &args[1];
+    let extension = &file_path[file_path.len()-2..file_path.len()];
+    if extension != "sr" {
+	error!("File is not in .sr");
+	std::process::exit(-1);
+    }
+    info!("File: {}", file_path);
     let file = File::open(&args[1])?;
     let reader = BufReader::new(file);