diff --git a/src/main.rs b/src/main.rs
index 095e7c2..6dc04f9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -17,7 +17,7 @@ const CONTEXT_KEY_LINENUM_SHORT: &str = "LN";
 fn main() {
     let mut exit_code = 0;
 
-    let options = Options::from_args();
+    let options = Options::from_args().with_defaults();
     let rargs = Arc::new(Rargs::new(&options));
 
     let stdin = io::stdin();
@@ -157,6 +157,15 @@ struct Options {
     cmd_and_args: Vec<String>,
 }
 
+impl Options {
+    pub fn with_defaults(mut self) -> Options {
+        if self.cmd_and_args.len() == 1 {
+            self.cmd_and_args.push("{}".to_string());
+        }
+        self
+    }
+}
+
 #[derive(Debug)]
 struct Rargs {
     pattern: Regex,