Using http-conduit to merely print the response is cumbersome.

ConduitSnippet.hs

{-# LANGUAGE OverloadedStrings #-}

import Data.CaseInsensitive (original)
import Data.Conduit (($$), yield)
import Data.Conduit.Binary (sinkHandle)
import Network.HTTP.Conduit
import Network.HTTP.Types
import System.IO (stdout)
import qualified Data.ByteString.Char8 as S

main :: IO ()
main = do
    req <- parseUrl "http://google.com/"

    withManager $ \m -> do
        res <- http req m

        (do yieldLn $ showStatus res
            yieldLn $ showHeaders res
            responseBody res) $$ sinkHandle stdout
  where yieldLn x = yield x >> yield "\n"

showStatus :: Response b -> S.ByteString
showStatus res = S.unwords [ S.pack . show . responseVersion $ res
                           , S.pack . show . statusCode $ responseStatus res
                           , statusMessage $ responseStatus res ]

showHeaders :: Response b -> S.ByteString
showHeaders = S.intercalate "\n" . map showHeader . responseHeaders
  where showHeader (k,v) = S.intercalate ": " [original k, v]