diff --git a/ShellCheck.cabal b/ShellCheck.cabal
index 9990531..48b492e 100644
--- a/ShellCheck.cabal
+++ b/ShellCheck.cabal
@@ -46,13 +46,14 @@ library
       regex-tdfa,
       QuickCheck >= 2.7.4
     exposed-modules:
-      ShellCheck.Checker
-      ShellCheck.Analyzer
-      ShellCheck.Parser
-      ShellCheck.Analytics
       ShellCheck.AST
+      ShellCheck.Analytics
+      ShellCheck.Analyzer
+      ShellCheck.Checker
       ShellCheck.Data
+      ShellCheck.Formatter.Format
       ShellCheck.Interface
+      ShellCheck.Parser
       ShellCheck.Regex
     other-modules:
       Paths_ShellCheck
diff --git a/ShellCheck/Analytics.hs b/ShellCheck/Analytics.hs
index b39b2f8..f8874f7 100644
--- a/ShellCheck/Analytics.hs
+++ b/ShellCheck/Analytics.hs
@@ -372,7 +372,10 @@ producesComments f s = do
         root <- prRoot pResult
         return . not . null $ runList (defaultSpec root) [f]
   where
-    pSpec = ParseSpec { psScript = s }
+    pSpec = ParseSpec {
+        psFilename = "script",
+        psScript = s
+    }
     pResult = runIdentity $ parseScript (mockedSystemInterface []) pSpec
 
 -- Copied from https://wiki.haskell.org/Edit_distance
diff --git a/ShellCheck/Checker.hs b/ShellCheck/Checker.hs
index 7700c56..91e61d8 100644
--- a/ShellCheck/Checker.hs
+++ b/ShellCheck/Checker.hs
@@ -47,18 +47,22 @@ checkScript :: Monad m => SystemInterface m -> CheckSpec -> m CheckResult
 checkScript sys spec = do
     results <- checkScript (csScript spec)
     return CheckResult {
+        crFilename = csFilename spec,
         crComments = results
     }
   where
     checkScript contents = do
-        result <- parseScript sys ParseSpec { psScript = contents }
+        result <- parseScript sys ParseSpec {
+            psFilename = csFilename spec,
+            psScript = contents
+        }
         let parseMessages = prComments result
         let analysisMessages =
                 fromMaybe [] $
                     (arComments . analyzeScript . analysisSpec)
                         <$> prRoot result
         let translator = tokenToPosition (prTokenPositions result)
-        return . sortMessages . filter shouldInclude $
+        return . nub . sortMessages . filter shouldInclude $
             (parseMessages ++ map translator analysisMessages)
 
     shouldInclude (PositionedComment _ (Comment _ code _)) =
@@ -66,7 +70,7 @@ checkScript sys spec = do
 
     sortMessages = sortBy (comparing order)
     order (PositionedComment pos (Comment severity code message)) =
-        (posFile pos, posLine pos, posColumn pos, code, message)
+        (posFile pos, posLine pos, posColumn pos, severity, code, message)
     getPosition (PositionedComment pos _) = pos
 
     analysisSpec root =
diff --git a/ShellCheck/Formatter/CheckStyle.hs b/ShellCheck/Formatter/CheckStyle.hs
new file mode 100644
index 0000000..9bd7166
--- /dev/null
+++ b/ShellCheck/Formatter/CheckStyle.hs
@@ -0,0 +1,82 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    http://www.vidarholen.net/contents/shellcheck
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.CheckStyle (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.Char
+import Data.List
+import GHC.Exts
+import System.IO
+
+format :: IO Formatter
+format = return Formatter {
+    header = do
+        putStrLn "<?xml version='1.0' encoding='UTF-8'?>"
+        putStrLn "<checkstyle version='4.3'>",
+
+    onFailure = outputError,
+    onResult = outputResult,
+
+    footer = putStrLn "</checkstyle>"
+}
+
+outputResult result contents = do
+    let comments = makeNonVirtual (crComments result) contents
+    putStrLn . formatFile (crFilename result) $ comments
+
+formatFile name comments = concat [
+    "<file ", attr "name" name, ">\n",
+        concatMap formatComment comments,
+    "</file>"
+    ]
+
+formatComment c = concat [
+    "<error ",
+    attr "line" $ show . lineNo $ c,
+    attr "column" $ show . colNo $ c,
+    attr "severity" . severity $ severityText c,
+    attr "message" $ messageText c,
+    attr "source" $ "ShellCheck.SC" ++ show (codeNo c),
+    "/>\n"
+    ]
+
+outputError file error = putStrLn $ concat [
+    "<file ", attr "name" file, ">\n",
+    "<error ",
+        attr "line" "1",
+        attr "column" "1",
+        attr "severity" "error",
+        attr "message" error,
+        attr "source" "ShellCheck",
+    "/>\n",
+    "</file>"
+    ]
+
+
+attr s v = concat [ s, "='", escape v, "' " ]
+escape = concatMap escape'
+escape' c = if isOk c then [c] else "&#" ++ show (ord c) ++ ";"
+isOk x = any ($x) [isAsciiUpper, isAsciiLower, isDigit, (`elem` " ./")]
+
+severity "error" = "error"
+severity "warning" = "warning"
+severity _ = "info"
diff --git a/ShellCheck/Formatter/Format.hs b/ShellCheck/Formatter/Format.hs
new file mode 100644
index 0000000..d9bfaa9
--- /dev/null
+++ b/ShellCheck/Formatter/Format.hs
@@ -0,0 +1,61 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    http://www.vidarholen.net/contents/shellcheck
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.Format where
+
+import ShellCheck.Data
+import ShellCheck.Interface
+
+-- A formatter that carries along an arbitrary piece of data
+data Formatter = Formatter {
+    header ::  IO (),
+    onResult :: CheckResult -> String -> IO (),
+    onFailure :: FilePath -> ErrorMessage -> IO (),
+    footer :: IO ()
+}
+
+lineNo (PositionedComment pos _) = posLine pos
+colNo  (PositionedComment pos _) = posColumn pos
+codeNo (PositionedComment _ (Comment _ code _)) = code
+messageText (PositionedComment _ (Comment _ _ t)) = t
+
+severityText :: PositionedComment -> String
+severityText (PositionedComment _ (Comment c _ _)) =
+    case c of
+        ErrorC   -> "error"
+        WarningC -> "warning"
+        InfoC    -> "info"
+        StyleC   -> "style"
+
+-- Realign comments from a tabstop of 8 to 1
+makeNonVirtual comments contents =
+    map fix comments
+  where
+    ls = lines contents
+    fix c@(PositionedComment pos comment) = PositionedComment pos {
+        posColumn =
+            if lineNo c > 0 && lineNo c <= fromIntegral (length ls)
+            then real (ls !! fromIntegral (lineNo c - 1)) 0 0 (colNo c)
+            else colNo c
+    } comment
+    real _ r v target | target <= v = r
+    real [] r v _ = r -- should never happen
+    real ('\t':rest) r v target =
+        real rest (r+1) (v + 8 - (v `mod` 8)) target
+    real (_:rest) r v target = real rest (r+1) (v+1) target
diff --git a/ShellCheck/Formatter/GCC.hs b/ShellCheck/Formatter/GCC.hs
new file mode 100644
index 0000000..ae542bf
--- /dev/null
+++ b/ShellCheck/Formatter/GCC.hs
@@ -0,0 +1,54 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    http://www.vidarholen.net/contents/shellcheck
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.GCC (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.List
+import GHC.Exts
+import System.IO
+
+format :: IO Formatter
+format = return Formatter {
+    header = return (),
+    footer = return (),
+    onFailure = outputError,
+    onResult = outputResult
+}
+
+outputError file error = hPutStrLn stderr $ file ++ ": " ++ error
+
+outputResult result contents = do
+    let comments = makeNonVirtual (crComments result) contents
+    mapM_ (putStrLn . formatComment (crFilename result)) comments
+
+formatComment filename c = concat [
+    filename, ":",
+    show $ lineNo c, ":",
+    show $ colNo c, ": ",
+    case severityText c of
+        "error" -> "error"
+        "warning" -> "warning"
+        _ -> "note",
+    ": ",
+    concat . lines $ messageText c,
+    " [SC", show $ codeNo c, "]"
+  ]
diff --git a/ShellCheck/Formatter/JSON.hs b/ShellCheck/Formatter/JSON.hs
new file mode 100644
index 0000000..018db27
--- /dev/null
+++ b/ShellCheck/Formatter/JSON.hs
@@ -0,0 +1,58 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    http://www.vidarholen.net/contents/shellcheck
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.JSON (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.IORef
+import GHC.Exts
+import System.IO
+import Text.JSON
+
+format = do
+    ref <- newIORef []
+    return Formatter {
+        header = return (),
+        onResult = collectResult ref,
+        onFailure = outputError,
+        footer = finish ref
+    }
+
+instance JSON (PositionedComment) where
+  showJSON comment@(PositionedComment pos (Comment level code string)) = makeObj [
+      ("file", showJSON $ posFile pos),
+      ("line", showJSON $ posLine pos),
+      ("column", showJSON $ posColumn pos),
+      ("level", showJSON $ severityText comment),
+      ("code", showJSON code),
+      ("message", showJSON string)
+      ]
+
+  readJSON = undefined
+
+outputError file msg = hPutStrLn stderr $ file ++ ": " ++ msg
+collectResult ref result _ =
+    modifyIORef ref (\x -> crComments result ++ x)
+
+finish ref = do
+    list <- readIORef ref
+    putStrLn $ encodeStrict list
+
diff --git a/ShellCheck/Formatter/TTY.hs b/ShellCheck/Formatter/TTY.hs
new file mode 100644
index 0000000..0b8e5dc
--- /dev/null
+++ b/ShellCheck/Formatter/TTY.hs
@@ -0,0 +1,86 @@
+{-
+    Copyright 2012-2015 Vidar Holen
+
+    This file is part of ShellCheck.
+    http://www.vidarholen.net/contents/shellcheck
+
+    ShellCheck is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    ShellCheck is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+-}
+module ShellCheck.Formatter.TTY (format) where
+
+import ShellCheck.Interface
+import ShellCheck.Formatter.Format
+
+import Data.List
+import GHC.Exts
+import System.Info
+import System.IO
+
+format :: IO Formatter
+format = return Formatter {
+    header = return (),
+    footer = return (),
+    onFailure = outputError,
+    onResult = outputResult
+}
+
+colorForLevel level = 
+    case level of
+        "error"   -> 31 -- red
+        "warning" -> 33 -- yellow
+        "info"    -> 32 -- green
+        "style"   -> 32 -- green
+        "message" -> 1 -- bold
+        "source"  -> 0 -- none
+        otherwise -> 0 -- none
+    
+outputError file error = do
+    color <- getColorFunc
+    hPutStrLn stderr $ color "error" $ file ++ ": " ++ error
+
+outputResult result contents = do
+    color <- getColorFunc
+    let comments = crComments result
+    let fileLines = lines contents
+    let lineCount = fromIntegral $ length fileLines
+    let groups = groupWith lineNo comments
+    mapM_ (\x -> do
+        let lineNum = lineNo (head x)
+        let line = if lineNum < 1 || lineNum > lineCount
+                        then ""
+                        else fileLines !! fromIntegral (lineNum - 1)
+        putStrLn ""
+        putStrLn $ color "message" $
+           "In " ++ crFilename result ++" line " ++ show lineNum ++ ":"
+        putStrLn (color "source" line)
+        mapM_ (\c -> putStrLn (color (severityText c) $ cuteIndent c)) x
+        putStrLn ""
+      ) groups
+
+cuteIndent :: PositionedComment -> String
+cuteIndent comment =
+    replicate (fromIntegral $ colNo comment - 1) ' ' ++
+        "^-- " ++ code (codeNo comment) ++ ": " ++ messageText comment
+
+code code = "SC" ++ show code
+
+getColorFunc = do
+    term <- hIsTerminalDevice stdout
+    let windows = "mingw" `isPrefixOf` os
+    return $ if term && not windows then colorComment else const id
+  where
+    colorComment level comment =
+        ansi (colorForLevel level) ++ comment ++ clear
+    clear = ansi 0
+    ansi n = "\x1B[" ++ show n ++ "m"
diff --git a/ShellCheck/Interface.hs b/ShellCheck/Interface.hs
index 6616915..97c4d7a 100644
--- a/ShellCheck/Interface.hs
+++ b/ShellCheck/Interface.hs
@@ -31,16 +31,19 @@ data SystemInterface m = SystemInterface {
 
 -- ShellCheck input and output
 data CheckSpec = CheckSpec {
+    csFilename :: String,
     csScript :: String,
     csExcludedWarnings :: [Integer],
     csShellTypeOverride :: Maybe Shell
 } deriving (Show, Eq)
 
 data CheckResult = CheckResult {
+    crFilename :: String,
     crComments :: [PositionedComment]
 } deriving (Show, Eq)
 
 emptyCheckSpec = CheckSpec {
+    csFilename = "",
     csScript = "",
     csExcludedWarnings = [],
     csShellTypeOverride = Nothing
@@ -48,6 +51,7 @@ emptyCheckSpec = CheckSpec {
 
 -- Parser input and output
 data ParseSpec = ParseSpec {
+    psFilename :: String,
     psScript :: String
 } deriving (Show, Eq)
 
diff --git a/ShellCheck/Parser.hs b/ShellCheck/Parser.hs
index 666d376..a194902 100644
--- a/ShellCheck/Parser.hs
+++ b/ShellCheck/Parser.hs
@@ -2223,8 +2223,8 @@ runParser sys p filename contents =
             sys)
         initialSystemState
 
-parseShell sys contents = do
-    (result, state) <- runParser sys (parseWithNotes readScript) "" contents
+parseShell sys name contents = do
+    (result, state) <- runParser sys (parseWithNotes readScript) name contents
     case result of
         Right (script, tokenMap, notes) ->
             return ParseResult {
@@ -2267,7 +2267,7 @@ posToPos sp = Position {
 parseScript :: Monad m =>
         SystemInterface m -> ParseSpec -> m ParseResult
 parseScript sys spec =
-    parseShell sys (psScript spec)
+    parseShell sys (psFilename spec) (psScript spec)
 
 
 lt x = trace (show x) x
diff --git a/shellcheck.hs b/shellcheck.hs
index 130d1d9..3ce3c3d 100644
--- a/shellcheck.hs
+++ b/shellcheck.hs
@@ -21,27 +21,26 @@ import ShellCheck.Data
 import ShellCheck.Checker
 import ShellCheck.Interface
 
+import ShellCheck.Formatter.Format
+import qualified ShellCheck.Formatter.CheckStyle
+import qualified ShellCheck.Formatter.GCC
+import qualified ShellCheck.Formatter.JSON
+import qualified ShellCheck.Formatter.TTY
+
 import Control.Exception
 import Control.Monad
 import Control.Monad.Except
 import Data.Char
 import Data.Functor
 import Data.Either
-import Data.IORef
-import Data.List
 import qualified Data.Map as Map
 import Data.Maybe
 import Data.Monoid
-import GHC.Exts
-import GHC.IO.Device
 import Prelude hiding (catch)
 import System.Console.GetOpt
 import System.Environment
 import System.Exit
 import System.IO
-import System.Info
-import Text.JSON
-import qualified Data.Map as Map
 
 data Flag = Flag String String
 data Status =
@@ -51,26 +50,13 @@ data Status =
     | SupportFailure
     | SyntaxFailure
     | RuntimeException
-  deriving (Ord, Eq)
+  deriving (Ord, Eq, Show)
 
 instance Monoid Status where
     mempty = NoProblems
     mappend = max
 
-lineNo (PositionedComment pos _) = posLine pos
-colNo  (PositionedComment pos _) = posColumn pos
-codeNo (PositionedComment _ (Comment _ code _)) = code
-messageText (PositionedComment _ (Comment _ _ t)) = t
-
-severityText :: PositionedComment -> String
-severityText (PositionedComment _ (Comment c _ _)) =
-    case c of
-        ErrorC   -> "error"
-        WarningC -> "warning"
-        InfoC    -> "info"
-        StyleC   -> "style"
-
-header = "Usage: shellcheck [OPTIONS...] FILES..."
+usageHeader = "Usage: shellcheck [OPTIONS...] FILES..."
 options = [
     Option "e" ["exclude"]
         (ReqArg (Flag "exclude") "CODE1,CODE2..") "exclude types of warnings",
@@ -82,206 +68,24 @@ options = [
         (NoArg $ Flag "version" "true") "Print version information"
     ]
 
-printOut = lift . hPutStrLn stdout
 printErr = lift . hPutStrLn stderr
 
-instance JSON (PositionedComment) where
-  showJSON comment@(PositionedComment pos (Comment level code string)) = makeObj [
-      ("file", showJSON $ posFile pos),
-      ("line", showJSON $ posLine pos),
-      ("column", showJSON $ posColumn pos),
-      ("level", showJSON $ severityText comment),
-      ("code", showJSON code),
-      ("message", showJSON string)
-      ]
-    where
-
-  readJSON = undefined
-
-
 parseArguments :: [String] -> ExceptT Status IO ([Flag], [FilePath])
 parseArguments argv =
     case getOpt Permute options argv of
         (opts, files, []) -> return (opts, files)
         (_, _, errors) -> do
-            printErr $ concat errors ++ "\n" ++ usageInfo header options
+            printErr $ concat errors ++ "\n" ++ usageInfo usageHeader options
             throwError SyntaxFailure
 
+formats :: Map.Map String (IO Formatter)
 formats = Map.fromList [
-{-
-    ("json", forJson),
-    ("gcc", forGcc),
-    ("checkstyle", forCheckstyle),
--}
-    ("tty", forTty)
+    ("checkstyle", ShellCheck.Formatter.CheckStyle.format),
+    ("gcc", ShellCheck.Formatter.GCC.format),
+    ("json", ShellCheck.Formatter.JSON.format),
+    ("tty", ShellCheck.Formatter.TTY.format)
     ]
 
-forTty :: SystemInterface IO -> CheckSpec -> [FilePath] -> ExceptT Status IO ()
-forTty sys spec files = mapM_ doFile files
-  where
-    clear = ansi 0
-    ansi n = "\x1B[" ++ show n ++ "m"
-
-    colorForLevel "error" = 31 -- red
-    colorForLevel "warning" = 33 -- yellow
-    colorForLevel "info" = 32 -- green
-    colorForLevel "style" = 32 -- green
-    colorForLevel "message" = 1 -- bold
-    colorForLevel "source" = 0 -- none
-    colorForLevel _ = 0 -- none
-
-    colorComment level comment =
-        ansi (colorForLevel level) ++ comment ++ clear
-
-    doFile filename = do
-        contents <- lift $ inputFile filename
-        comments <- lift (crComments <$> checkScript sys spec { csScript = contents })
-        let fileLines = lines contents
-        let lineCount = fromIntegral $ length fileLines
-        let groups = groupWith lineNo comments
-        colorFunc <- getColorFunc
-        mapM_ (\x -> do
-            let lineNum = lineNo (head x)
-            let line = if lineNum < 1 || lineNum > lineCount
-                            then ""
-                            else fileLines !! (fromIntegral $ lineNum - 1)
-            printOut ""
-            printOut $ colorFunc "message"
-                ("In " ++ filename ++" line " ++ show lineNum ++ ":")
-            printOut (colorFunc "source" line)
-            mapM_ (\c -> printOut (colorFunc (severityText c) $ cuteIndent c)) x
-            printOut ""
-          ) groups
-
-    cuteIndent :: PositionedComment -> String
-    cuteIndent comment =
-        replicate (fromIntegral $ colNo comment - 1) ' ' ++
-            "^-- " ++ code (codeNo comment) ++ ": " ++ messageText comment
-
-    code code = "SC" ++ show code
-
-    getColorFunc = do
-        term <- lift $ hIsTerminalDevice stdout
-        let windows = "mingw" `isPrefixOf` os
-        return $ if term && not windows then colorComment else const id
-
-{-
-forJson :: a -> Formatter
-forJson _ result = do
-    let comments = concatMap getComments (crComments result)
-    lift $ putStrLn $ encodeStrict comments
-  where
-    getComments (_, FileResult comments) = comments
-    getComments (file, FileError str) = [
-        PositionedComment
-            Position {
-                posFile = file,
-                posLine = 1,
-                posColumn = 1
-            }
-            (Comment ErrorC 1000 str)
-        ]
-
--- Mimic GCC "file:line:col: (error|warning|note): message" format
-forGcc :: SystemInterface IO -> Formatter
-forGcc io result = do
-    mapM_ (uncurry process) (crComments result)
-  where
-    process filename (FileError string) = do
-        printErr $ string
-
-    process filename (FileResult result) = do
-        fileInput <- lift $ siReadFile io filename
-        when (isLeft fileInput) $ do
-            printErr $ "Failed to re-open " ++ filename
-            throwError RuntimeException
-        let contents = fromRight fileInput
-        let comments = makeNonVirtual result contents
-        mapM_ (printOut . format filename) comments
-
-    format filename c = concat [
-            filename, ":",
-            show $ lineNo c, ":",
-            show $ colNo c, ": ",
-            case severityText c of
-                "error" -> "error"
-                "warning" -> "warning"
-                _ -> "note",
-            ": ",
-            concat . lines $ messageText c,
-            " [SC", show $ codeNo c, "]"
-      ]
-
--- Checkstyle compatible output. A bit of a hack to avoid XML dependencies
-forCheckstyle :: SystemInterface IO -> Formatter
-forCheckstyle _ result = do
-    printOut "<?xml version='1.0' encoding='UTF-8'?>"
-    printOut "<checkstyle version='4.3'>"
-    statuses <- mapM process (crComments result)
-    printOut "</checkstyle>"
-    return $ mconcat statuses
-  where
-    process (file, FileError str) =
-        printOut (formatError file str)
-
-    process (file, FileResult comments) =
-        printOut (formatFile file comments)
-
-    severity "error" = "error"
-    severity "warning" = "warning"
-    severity _ = "info"
-    attr s v = concat [ s, "='", escape v, "' " ]
-    escape = concatMap escape'
-    escape' c = if isOk c then [c] else "&#" ++ show (ord c) ++ ";"
-    isOk x = any ($x) [isAsciiUpper, isAsciiLower, isDigit, (`elem` " ./")]
-
-    formatFile name comments = concat [
-        "<file ", attr "name" name, ">\n",
-            concatMap format comments,
-        "</file>"
-        ]
-
-    format c = concat [
-        "<error ",
-        attr "line" $ show . lineNo $ c,
-        attr "column" $ show . colNo $ c,
-        attr "severity" . severity $ severityText c,
-        attr "message" $ messageText c,
-        attr "source" $ "ShellCheck.SC" ++ show (codeNo c),
-        "/>\n"
-        ]
-
-    formatError file msg = concat [
-        "<file ", attr "name" file, ">\n",
-        "<error ",
-            attr "line" "1",
-            attr "column" "1",
-            attr "severity" $ severity "error",
-            attr "message" msg,
-            attr "source" "ShellCheck",
-        "/>\n",
-        "</file>"
-        ]
--}
-
-
--- Realign comments from a tabstop of 8 to 1
-makeNonVirtual comments contents =
-    map fix comments
-  where
-    ls = lines contents
-    fix c@(PositionedComment pos comment) = PositionedComment pos {
-        posColumn =
-            if lineNo c > 0 && lineNo c <= fromIntegral (length ls)
-            then real (ls !! (fromIntegral $ lineNo c - 1)) 0 0 (colNo c)
-            else colNo c
-    } comment
-    real _ r v target | target <= v = r
-    real [] r v _ = r -- should never happen
-    real ('\t':rest) r v target =
-        real rest (r+1) (v + 8 - (v `mod` 8)) target
-    real (_:rest) r v target = real rest (r+1) (v+1) target
-
 getOption [] _ = Nothing
 getOption (Flag var val:_) name | name == var = return val
 getOption (_:rest) flag = getOption rest flag
@@ -304,12 +108,7 @@ getExclusions options =
     in
         map (Prelude.read . clean) elements :: [Int]
 
-excludeCodes codes =
-    filter (not . hasCode)
-  where
-    hasCode c = codeNo c `elem` codes
-
-toStatus = liftM (either id (const NoProblems)) . runExceptT
+toStatus = liftM (either id id) . runExceptT
 
 main = do
     args <- getArgs
@@ -327,7 +126,7 @@ statusToCode status =
         SupportFailure -> ExitFailure 4
         RuntimeException -> ExitFailure 2
 
-process :: [Flag] -> [FilePath] -> ExceptT Status IO ()
+process :: [Flag] -> [FilePath] -> ExceptT Status IO Status
 process flags files = do
     options <- foldM (flip parseOption) emptyCheckSpec flags
     verifyFiles files
@@ -340,9 +139,40 @@ process flags files = do
                 mapM_ (printErr . write) $ Map.keys formats
                 throwError SupportFailure
               where write s = "  " ++ s
-            Just f -> ExceptT $ fmap Right $ return f
+            Just f -> ExceptT $ fmap Right f
     let sys = ioInterface (const False)
-    formatter sys options files
+    lift $ runFormatter sys formatter options files
+
+runFormatter :: SystemInterface IO -> Formatter -> CheckSpec -> [FilePath]
+            -> IO Status
+runFormatter sys format spec files = do
+    header format
+    result <- foldM f NoProblems files
+    footer format
+    return result
+  where
+    f :: Status -> FilePath -> IO Status
+    f status file = do
+        newStatus <- process file `catch` handler file
+        return $ status `mappend` newStatus
+    handler :: FilePath -> IOException -> IO Status
+    handler file e = do
+        onFailure format file (show e)
+        return RuntimeException
+
+    process :: FilePath -> IO Status
+    process filename = do
+        contents <- inputFile filename
+        let checkspec = spec {
+            csFilename = filename,
+            csScript = contents
+        }
+        result <- checkScript sys checkspec
+        onResult format result contents
+        return $
+            if null (crComments result)
+            then NoProblems
+            else SomeProblems
 
 parseOption flag options =
     case flag of
@@ -372,12 +202,12 @@ parseOption flag options =
             throwError SyntaxFailure
         return (Prelude.read num :: Integer)
 
-ioInterface filter = do
+ioInterface filter =
     SystemInterface {
         siReadFile = get
     }
   where
-    get file = do
+    get file =
         if filter file
           then (Right <$> inputFile file) `catch` handler
           else return $ Left (file ++ " was not specified as input.")
@@ -390,12 +220,14 @@ inputFile file = do
             if file == "-"
             then getContents
             else readFile file
-    return contents
+
+    seq (length contents) $
+        return contents
 
 verifyFiles files =
     when (null files) $ do
         printErr "No files specified.\n"
-        printErr $ usageInfo header options
+        printErr $ usageInfo usageHeader options
         throwError SyntaxFailure
 
 printVersion = do