diff --git a/src/cat.rs b/src/cat.rs
index cb81066..e3b09a1 100644
--- a/src/cat.rs
+++ b/src/cat.rs
@@ -18,10 +18,9 @@
  */
 
 use std::env;
-use std::fs::{File, read, read_to_string};
+use std::fs::{File, read_to_string};
 use std::io;
-use std::io::{ Read, Write };
-use std::os::unix::io::FromRawFd;
+use std::io::{ BufRead, Read };
 use std::str;
 
 use arg::Args;
@@ -50,6 +49,33 @@ fn main() -> ExitCode {
 
   if args.paths.is_empty() { args.paths.push("-".to_string()); }
 
+  while args.u {
+    for path in &args.paths {
+      if path == "-" {
+        loop {
+          let mut buf = String::new();
+          match io::stdin().lock().read_line(&mut buf) {
+            Ok(bytes) => {
+              if bytes == 0 { break };
+              print!("{}", buf);
+            },
+            Err(err) => println!("{}", err),
+          };
+        }
+      } else {
+        let mut input = String::new();
+        match File::open(path) {
+          Ok(input) => {},
+          Err(_) => {
+            println!("{}: {}: No such file or directory.", &argv0, path);
+            return ExitCode::NoInput;
+          },
+        };
+      }
+    }
+    return ExitCode::Ok;
+  }
+
   for path in args.paths {
     if path == "-" {
       let mut bytes: Vec<u8> = Vec::new();