diff --git a/src/comm/comm.rs b/src/comm/comm.rs
index 60a2b6beb..505a70a30 100644
--- a/src/comm/comm.rs
+++ b/src/comm/comm.rs
@@ -14,7 +14,7 @@ extern crate getopts;
 use std::cmp::Ord;
 use std::io::{BufferedReader, IoResult, print};
 use std::io::fs::File;
-use std::io::stdio::stdin;
+use std::io::stdio::{stdin, StdReader};
 use std::path::Path;
 
 static NAME : &'static str = "comm";
@@ -44,7 +44,21 @@ fn ensure_nl(line: String) -> String {
     }
 }
 
-fn comm(a: &mut Box<Buffer>, b: &mut Box<Buffer>, opts: &getopts::Matches) {
+enum LineReader {
+    Stdin(BufferedReader<StdReader>),
+    FileIn(BufferedReader<File>)
+}
+
+impl LineReader {
+    fn read_line(&mut self) -> IoResult<String> {
+        match self {
+            &Stdin(ref mut r)  => r.read_line(),
+            &FileIn(ref mut r) => r.read_line(),
+        }
+    }
+}
+
+fn comm(a: &mut LineReader, b: &mut LineReader, opts: &getopts::Matches) {
 
     let delim = Vec::from_fn(4, |col| mkdelim(col, opts));
 
@@ -83,12 +97,12 @@ fn comm(a: &mut Box<Buffer>, b: &mut Box<Buffer>, opts: &getopts::Matches) {
     }
 }
 
-fn open_file(name: &str) -> IoResult<Box<Buffer>> {
+fn open_file(name: &str) -> IoResult<LineReader> {
     match name {
-        "-" => Ok(box stdin() as Box<Buffer>),
+        "-" => Ok(LineReader::Stdin(stdin())),
         _   => {
-            let f = try!(File::open(&Path::new(name)));
-            Ok(box BufferedReader::new(f) as Box<Buffer>)
+            let f = try!(std::io::File::open(&Path::new(name)));
+            Ok(LineReader::FileIn(BufferedReader::new(f)))
         }
     }
 }
diff --git a/src/shuf/shuf.rs b/src/shuf/shuf.rs
index 4d5394be0..7441e0b32 100644
--- a/src/shuf/shuf.rs
+++ b/src/shuf/shuf.rs
@@ -19,7 +19,7 @@ use std::from_str::from_str;
 use std::io;
 use std::io::IoResult;
 use std::iter::{range_inclusive, RangeInclusive};
-use std::rand;
+use std::rand::{mod, Rng};
 use std::uint;
 
 #[path = "../common/util.rs"]
@@ -151,14 +151,28 @@ fn shuf(input: Vec<String>, mode: Mode, repeat: bool, zero: bool, count: uint, o
     }
 }
 
+enum WrappedRng {
+    RngFile(rand::reader::ReaderRng<io::File>),
+    RngDefault(rand::TaskRng),
+}
+
+impl WrappedRng {
+    fn next_u32(&mut self) -> u32 {
+        match self {
+            &RngFile(ref mut r) => r.next_u32(),
+            &RngDefault(ref mut r) => r.next_u32(),
+        }
+    }
+}
+
 fn shuf_lines(mut lines: Vec<String>, repeat: bool, zero: bool, count: uint, outname: Option<String>, random: Option<String>) -> IoResult<()> {
     let mut output = match outname {
         Some(name) => box io::BufferedWriter::new(try!(io::File::create(&Path::new(name)))) as Box<Writer>,
         None => box io::stdout() as Box<Writer>
     };
     let mut rng = match random {
-        Some(name) => box rand::reader::ReaderRng::new(try!(io::File::open(&Path::new(name)))) as Box<rand::Rng>,
-        None => box rand::task_rng() as Box<rand::Rng>
+        Some(name) => RngFile(rand::reader::ReaderRng::new(try!(io::File::open(&Path::new(name))))),
+        None => RngDefault(rand::task_rng()),
     };
     let mut len = lines.len();
     let max = if repeat { count } else { cmp::min(count, len) };