diff --git a/System/Posix/Redirect.hs b/System/Posix/Redirect.hs
--- a/System/Posix/Redirect.hs
+++ b/System/Posix/Redirect.hs
@@ -41,6 +41,8 @@
 import Foreign
 import Foreign.C.Types
 
+import Data.ByteString as BS
+
 import Control.Concurrent
 import Control.Exception
 
@@ -53,7 +55,7 @@
 -- descriptor is restored.  Use with care: if there are any file
 -- handles with this descriptor that have unflushed buffers, they will
 -- not flush to the old file descriptor, but the new file descriptor.
-unsafeRedirectWriteFd :: Fd -> IO a -> IO (String, a)
+unsafeRedirectWriteFd :: Fd -> IO a -> IO (ByteString, a)
 unsafeRedirectWriteFd fd f = do
     -- setup
     (rfd, wfd) <- createPipe
@@ -62,17 +64,14 @@
     -- fork a thread to consume output
     outMVar <- newEmptyMVar
     outHandle <- fdToHandle rfd
-    out <- hGetContents outHandle
-    _ <- forkIO $ do
-        _ <- evaluate (length out)
-        putMVar outMVar ()
+    _ <- forkIO (BS.hGetContents outHandle >>= putMVar outMVar)
     -- run the code
     r <- f
     -- cleanup
     dupTo_ old fd
     closeFd wfd
     -- wait for output
-    takeMVar outMVar
+    out <- takeMVar outMVar
     hClose outHandle
     return (out, r)
 
@@ -81,7 +80,7 @@
 -- end of a pipe that @fd@ now points to.  This function appropriately
 -- flushes the Haskell @oldHandle@ and the C @oldCHandle@ before
 -- and after @f@'s execution.
-redirectWriteHandle :: Fd -> Handle -> Ptr FILE -> IO a -> IO (String, a)
+redirectWriteHandle :: Fd -> Handle -> Ptr FILE -> IO a -> IO (ByteString, a)
 redirectWriteHandle oldFd oldHandle cOldHandle f = do
     hFlush oldHandle
     hFlush stdout
@@ -92,16 +91,16 @@
         _ <- c_fflush cOldHandle
         return r
 
--- | @'redirectStdout f' redirects standard output during the execution
+-- | @'redirectStdout' f@ redirects standard output during the execution
 -- of @f@ into a pipe passed as the first argument to @f@.
-redirectStdout :: IO a -> IO (String, a)
+redirectStdout :: IO a -> IO (ByteString, a)
 redirectStdout f = do
     c_stdout <- cio_stdout
     redirectWriteHandle stdOutput stdout c_stdout f
 
--- | @'redirectStderr f' redirects standard error during the execution
+-- | @'redirectStderr' f@ redirects standard error during the execution
 -- of @f@ into a pipe passed as the first argument to @f@.
-redirectStderr :: IO a -> IO (String, a)
+redirectStderr :: IO a -> IO (ByteString, a)
 redirectStderr f = do
     c_stderr <- cio_stderr
     redirectWriteHandle stdError stderr c_stderr f
diff --git a/system-posix-redirect.cabal b/system-posix-redirect.cabal
--- a/system-posix-redirect.cabal
+++ b/system-posix-redirect.cabal
@@ -1,5 +1,5 @@
 Name:               system-posix-redirect
-Version:            1.0.0.1
+Version:            1.1
 Synopsis:           A toy module that allows you to temporarily redirect
                     a program's stdout.
 Description:        Due to the design of POSIX, it is possible to
@@ -33,7 +33,7 @@
   Exposed-modules:      System.Posix.Redirect
   Extensions:           ForeignFunctionInterface,
                         EmptyDataDecls
-  Build-depends:        base >= 4 && < 5, unix >= 2.4.0
+  Build-depends:        base >= 4 && < 5, bytestring >= 0.9, unix >= 2.4.0
   C-sources:            cbits/hsredirect.c
   Include-dirs:         include
   Install-includes:     include/hsredirect.h