diff --git a/deps/Cargo.toml b/deps/Cargo.toml
index 622eef41d..0915db569 100644
--- a/deps/Cargo.toml
+++ b/deps/Cargo.toml
@@ -7,6 +7,7 @@ name = "null"
 
 [dependencies]
 libc = "0.1.6"
+num_cpus = "*"
 rand = "0.3.8"
 regex = "0.1.30"
 regex_macros = "0.1.17"
diff --git a/src/nproc/deps.mk b/src/nproc/deps.mk
new file mode 100644
index 000000000..8bd1a6c62
--- /dev/null
+++ b/src/nproc/deps.mk
@@ -0,0 +1 @@
+DEPLIBS += num_cpus
diff --git a/src/nproc/nproc.rs b/src/nproc/nproc.rs
index 2d5cd57ac..dc3ad1935 100644
--- a/src/nproc/nproc.rs
+++ b/src/nproc/nproc.rs
@@ -1,5 +1,5 @@
 #![crate_name = "nproc"]
-#![feature(collections, os, rustc_private)]
+#![feature(rustc_private)]
 
 /*
  * This file is part of the uutils coreutils package.
@@ -11,8 +11,10 @@
  */
 
 extern crate getopts;
+extern crate num_cpus;
 
-use std::os;
+use std::env;
+use std::io::Write;
 
 static NAME : &'static str = "nproc";
 static VERSION : &'static str = "0.0.0";
@@ -29,7 +31,7 @@ pub fn uumain(args: Vec<String>) -> i32 {
         getopts::optflag("V", "version", "output version information and exit"),
     ];
 
-    let matches = match getopts::getopts(args.tail(), &opts) {
+    let matches = match getopts::getopts(&args[1..], &opts) {
         Ok(m) => m,
         Err(err) => {
             show_error!("{}", err);
@@ -46,7 +48,7 @@ pub fn uumain(args: Vec<String>) -> i32 {
         println!("{} {}", NAME, VERSION);
         println!("");
         println!("Usage:");
-        println!("  {} [OPTIONS] NAME...", NAME);
+        println!("  {} [OPTIONS]...", NAME);
         println!("");
         print!("{}", getopts::usage("Print the number of cores available to the current process.", &opts));
         return 0;
@@ -64,16 +66,16 @@ pub fn uumain(args: Vec<String>) -> i32 {
     };
 
     if !matches.opt_present("all") {
-        ignore += match os::getenv("OMP_NUM_THREADS") {
-            Some(threadstr) => match threadstr.parse() {
+        ignore += match env::var("OMP_NUM_THREADS") {
+            Ok(threadstr) => match threadstr.parse() {
                 Ok(num) => num,
                 Err(_)=> 0
             },
-            None => 0
+            Err(_) => 0
         };
     }
 
-    let mut cores = os::num_cpus();
+    let mut cores = num_cpus::get();
     if cores <= ignore {
         cores = 1;
     } else {