Process stdin instead of opening a file path.

src/main.rs

@@ -1,5 +1,5 @@
 use std::{
-    fs::File,
+    // fs::File,
     io::{Cursor, Read},
 };
 
@@ -24,10 +24,7 @@ fn main() {
 
     let text = {
         let mut text = String::new();
-        File::open(std::env::args().nth(1).unwrap())
-            .unwrap()
-            .read_to_string(&mut text)
-            .unwrap();
+        std::io::stdin().read_to_string(&mut text).unwrap();
         text
     };