diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,31 +1,24 @@
-Copyright Yusaku Hashimoto 2009
-
+Copyright (c) 2016 Mitchell Rosen
 All rights reserved.
 
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are met:
-
-    * Redistributions of source code must retain the above copyright
-      notice, this list of conditions and the following disclaimer.
-
-    * Redistributions in binary form must reproduce the above
-      copyright notice, this list of conditions and the following
-      disclaimer in the documentation and/or other materials provided
-      with the distribution.
-
-    * Neither the name of Yusaku Hashimoto nor the names of other
-      contributors may be used to endorse or promote products derived
-      from this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+    * Redistributions of source code must retain the above copyright notice,
+      this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright notice,
+      this list of conditions and the following disclaimer in the documentation
+      and/or other materials provided with the distribution.
+    * Neither the name of Mitchell Rosen nor the names of other contributors
+      may be used to endorse or promote products derived from this software
+      without specific prior written permission.
 
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Setup.lhs b/Setup.lhs
deleted file mode 100644
--- a/Setup.lhs
+++ /dev/null
@@ -1,3 +0,0 @@
-#!/usr/bin/env runhaskell
-> import Distribution.Simple
-> main = defaultMain
diff --git a/System/IO/Capture.hs b/System/IO/Capture.hs
deleted file mode 100644
--- a/System/IO/Capture.hs
+++ /dev/null
@@ -1,87 +0,0 @@
-{-# LANGUAGE ScopedTypeVariables #-}
-
-module System.IO.Capture (
-  -- * As usual, You specify import only this function.
-  capture
-
-  -- * If you want to use lazy reading in the action, I recomend you use these.
-, getContents
-, hGetContents
-, readFile
-) where
-
-import Prelude hiding (getContents,readFile,catch)
-import System.IO hiding (getContents,hGetContents,readFile)
-import qualified System.IO.Strict as SIO (getContents,hGetContents,readFile)
-    -- in package strict (not in strict-io)
-import Control.Exception
-import Control.Applicative
-import Control.Monad
-import System.Directory
-import System.Posix
-
-{-|
-
-  Takes an IO as action to run, and a String as given stdin,
-  then returns whole stdout and stderr as String of tuple.
-
-  > import System.IO.Capture (capture)
-  >
-  > main = print =<< capture (getLine >>= putStr) "foobar"
-  >   -- prints ("foobar","")
-
-  WARNING: If Lazy Reading such as @getContents@ was contained in the
-  action, its behavior is very strange. For detail, see
-  tests/Tests.hs.
-
- -}
-
-capture :: IO a -> String -> IO (String,String)
-capture action givenInput = 
-  withTempFile $ \(outh,outpath) ->
-  withTempFile $ \(errh,errpath) -> ignoringException ("","") $ do
-    let stds =  [stdin,stdout,stderr]
-    stdbufs <- mapM hGetBuffering stds
-    mapM_ (flip hSetBuffering NoBuffering) stds
-    (inr,inw) <- createPipe
-    fd_in  <- dup 0
-    fd_out <- dup 1
-    fd_err <- dup 2
-    let capture' = do
-          inr `dupTo` 0
-          flip dupTo 1 =<< handleToFd outh
-          flip dupTo 2 =<< handleToFd errh
-          fdWrite inw givenInput
-          closeFd inw
-          ignoringException () (action >> return ())
-          (,) <$> readFile outpath <*> readFile errpath
-        recover = do
-          fd_in  `dupTo` 0
-          fd_out `dupTo` 1
-          fd_err `dupTo` 2
-          forM_ [inr,inw,fd_in,fd_out,fd_err] $ \fd -> ignoringException () $ closeFd fd
-          zipWithM_ ((ignoringException () .) . hSetBuffering) stds stdbufs
-    capture' `finally` recover
-
--- override for forcing strictness
-
--- if exception was thrown, they returns empty string.
-
-readFile     :: FilePath -> IO String
-getContents  :: IO String
-hGetContents :: Handle -> IO String
-
-readFile     = ignoringException "" . SIO.readFile
-getContents  = ignoringException "" SIO.getContents
-hGetContents = ignoringException "" . SIO.hGetContents
-
--- utilities
-
-withTempFile :: ((Handle,FilePath) -> IO a) -> IO a
-withTempFile action = do
-  (path,hdl) <- flip openTempFile "tmpXXXXX" =<< getTemporaryDirectory
-  action (hdl,path) `finally` (hClose hdl >> removeFile path)
-
-ignoringException :: a -> IO a -> IO a
-ignoringException value action = action `catch` do \(_::SomeException) -> return value
-
diff --git a/io-capture.cabal b/io-capture.cabal
--- a/io-capture.cabal
+++ b/io-capture.cabal
@@ -1,16 +1,48 @@
-name:                io-capture
-version:             0.1
-synopsis:            capture IO action's stdout and stderr
-description:         capture IO action's stdout and stderr
-category:            System
-license:             BSD3
-license-file:        LICENSE
-author:              Yusaku Hashimoto
-maintainer:          nonowarn@gmail.com
-build-depends:       base >= 4 && < 5, unix, strict, directory
-build-type:          Simple
-ghc-options:         -Wall
+-- This file has been generated from package.yaml by hpack version 0.9.0.
+--
+-- see: https://github.com/sol/hpack
 
-exposed-modules:     System.IO.Capture
+name:           io-capture
+version:        0.1.0.0
+synopsis:       Capture IO actions' stdout and stderr
+description:    Capture IO actions' stdout and stderr
+homepage:       https://github.com/mitchellwrosen/io-capture#readme
+bug-reports:    https://github.com/mitchellwrosen/io-capture/issues
+author:         Mitchell Rosen
+maintainer:     mitchellwrosen@gmail.com
+copyright:      2016 Mitchell Rosen
+license:        BSD3
+license-file:   LICENSE
+build-type:     Simple
+cabal-version:  >= 1.10
 
-extra-source-files:  tests/Tests.hs
+source-repository head
+  type: git
+  location: https://github.com/mitchellwrosen/io-capture
+
+library
+  hs-source-dirs:
+      src
+  ghc-options: -Wall
+  build-depends:
+      base <5.0
+    , bytestring <0.11
+    , streaming-bytestring <0.2
+    , unix <2.8
+  exposed-modules:
+      System.IO.Capture
+  default-language: Haskell2010
+
+test-suite spec
+  type: exitcode-stdio-1.0
+  main-is: tests/Spec.hs
+  ghc-options: -Wall
+  build-depends:
+      base <5.0
+    , bytestring <0.11
+    , streaming-bytestring <0.2
+    , unix <2.8
+    , hspec
+    , hspec-core
+    , io-capture
+  default-language: Haskell2010
diff --git a/src/System/IO/Capture.hs b/src/System/IO/Capture.hs
new file mode 100644
--- /dev/null
+++ b/src/System/IO/Capture.hs
@@ -0,0 +1,106 @@
+{-# LANGUAGE LambdaCase          #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module System.IO.Capture
+  ( capture
+  , captureStream
+  ) where
+
+import Control.Exception
+import Control.Monad
+import System.IO            (hClose, hPutStr)
+import System.Posix.IO
+import System.Posix.Process
+import System.Posix.Types   (ProcessID)
+
+import qualified Data.ByteString.Lazy      as LBS
+import qualified Data.ByteString.Streaming as S
+
+-- For haddocks
+import Data.ByteString.Streaming (stdout)
+
+-- | Capture an IO action's @stdout@, @stderr@, and any thrown exception. Waits
+-- for the action to complete before returning.
+--
+-- @
+-- > (out, _, _, _) <- 'capture' ('putStrLn' "foo")
+-- > 'print' out
+-- \"foo\"
+--
+-- > (_, err, _, _) <- 'capture' ('System.IO.hPutStrLn' 'System.IO.stderr' \"bar\")
+-- > 'print' err
+-- \"bar\"
+--
+-- > (_, _, exc, _) <- 'capture' 'undefined'
+-- > 'print' exc
+-- \"Prelude.undefined\"
+-- @
+capture :: IO a -> IO (LBS.ByteString, LBS.ByteString, LBS.ByteString, Maybe ProcessStatus)
+capture act = do
+  (out, err, exc, pid) <- captureStream act
+  status <- getProcessStatus True True pid
+  (,,,)
+    <$> S.toLazy_ out
+    <*> S.toLazy_ err
+    <*> S.toLazy_ exc
+    <*> pure status
+
+-- | Stream an IO action's @stdout@, @stderr@, and any thrown exception. Also
+-- returns the spawned process's pid to @wait@ on (otherwise the process will
+-- become a zombie after terminating), kill, etc.
+--
+-- @
+-- import qualified Data.ByteString.Streaming as S
+--
+-- > let action = 'putStrLn' \"foo\" >> 'Control.Concurrent.threadDelay' 1000000
+-- > (out, _, _, pid) <- 'captureStream' ('Control.Monad.replicateM_' 5 action)
+-- > S.'stdout' out
+-- foo
+-- foo
+-- foo
+-- foo
+-- foo
+-- > 'getProcessStatus' True True pid
+-- Just ('Exited' 'System.Exit.ExitSuccess')
+-- @
+captureStream
+  :: IO a
+  -> IO ( S.ByteString IO ()
+        , S.ByteString IO ()
+        , S.ByteString IO ()
+        , ProcessID
+        )
+captureStream act = do
+  (out_r, out_w) <- createPipe
+  (err_r, err_w) <- createPipe
+  (exc_r, exc_w) <- createPipe
+
+  pid <- forkProcess $ do
+    closeFd out_r
+    closeFd err_r
+    closeFd exc_r
+
+    _ <- dupTo out_w stdOutput
+    _ <- dupTo err_w stdError
+
+    exc_wh <- fdToHandle exc_w
+
+    void act `catch` \(e :: SomeException) -> hPutStr exc_wh (show e)
+
+    closeFd out_w
+    closeFd err_w
+    hClose exc_wh
+
+  closeFd out_w
+  closeFd err_w
+  closeFd exc_w
+
+  out_rh <- fdToHandle out_r
+  err_rh <- fdToHandle err_r
+  exc_rh <- fdToHandle exc_r
+
+  pure ( S.hGetContents out_rh
+       , S.hGetContents err_rh
+       , S.hGetContents exc_rh
+       , pid
+       )
diff --git a/tests/Spec.hs b/tests/Spec.hs
new file mode 100644
--- /dev/null
+++ b/tests/Spec.hs
@@ -0,0 +1,44 @@
+{-# LANGUAGE LambdaCase        #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+import System.IO.Capture
+
+import Control.Concurrent
+import Control.Monad
+import System.IO
+import System.Posix.Process
+import System.Posix.Signals
+import System.Timeout
+import Test.Hspec
+import Test.Hspec.Core.Runner
+
+import qualified Data.ByteString.Streaming as S
+
+main :: IO ()
+main = hspecWith config $ do
+  describe "capture" $ do
+    it "captures everything" $ do
+      (out, err, exc, _) <- capture (putStr "foo" >> hPutStr stderr "bar" >> undefined)
+      out `shouldBe` "foo"
+      err `shouldBe` "bar"
+      exc `shouldBe` "Prelude.undefined"
+
+  describe "captureStream" $ do
+    it "streams output" $ do
+      (out, _, _, pid) <- captureStream (forever (putStrLn "foo" >> threadDelay (1*sec)))
+
+      timeout (2*sec) (S.uncons out) >>= \case
+        Just (Just _) -> do
+          signalProcess sigKILL pid
+          _ <- getProcessStatus True True pid
+          pure ()
+        _ -> expectationFailure "expected a byte, found nothing"
+
+
+ where
+  -- hspec in color mode messes with stdout
+  config = defaultConfig
+    { configColorMode = ColorNever }
+
+sec :: Int
+sec = 1000000
diff --git a/tests/Tests.hs b/tests/Tests.hs
deleted file mode 100644
--- a/tests/Tests.hs
+++ /dev/null
@@ -1,32 +0,0 @@
-import Test.Torch
-import Control.Monad.Trans
-import Prelude hiding (getContents)
-import System.IO (hPutStrLn,stderr)
-import System.IO.Capture (capture,getContents)
-
-main = run $ do
-  (out,err) <- liftIO $ capture (putStrLn "foo") []
-  is out "foo\n" "stdout is captured"
-  ok (null err)  "stderr is also captured"
-
-  (out,err) <- liftIO $ capture (getLine >>= putStrLn >>
-                                 getLine >>= hPutStrLn stderr)
-                                "foo\nbar\n"
-  is out "foo\n" "stdin can be given; stdout is still captured"
-  is err "bar\n" "stdin can be given; stderr is still captured"
-
-  (out,err) <- liftIO $ capture (getContents >>= putStr) "foobarbaz\nquux\n"
-  is out "foobarbaz\nquux\n" "lazy io also works; stdout captured"
-  ok (null err)              "lazy io also works; stderr captured"
-
-  (out,err) <- liftIO $ capture (getLine >>= putStrLn >>
-                                 getLine >>= hPutStrLn stderr)
-                                "foo\nbar\n"
-  isn't out "foo\n" "after lazy reading stdin, stdin is not can be given any more"
-  isn't err "bar\n" "after lazy reading stdin, stdin is not can be given any more"
-
-{-
-  (out,err) <- liftIO $ capture (putStrLn "foo") []
-  is out "foo\n" "but stdout is still captured, after lazy reading"
-  ok (null err)  "stderr is still also captured, after lazy reading"
- -}