diff --git a/omnicodec.cabal b/omnicodec.cabal
--- a/omnicodec.cabal
+++ b/omnicodec.cabal
@@ -1,20 +1,24 @@
 name: omnicodec
-version: 0.3
+version: 0.3.1
 license: GPL
 license-file: COPYING
 author: Magnus Therning
 maintainer: magnus@therning.org
 copyright: Magnus Therning, 2007
 synopsis: data encoding and decoding command line utilities
-description: Two simply command line tools built on dataenc.
-build-depends: base >= 4.0.0 && < 4.2, dataenc >= 0.13, directory, filepath, haskell98
+description: Two simple command line tools built on dataenc.
 build-type: Simple
 category: Codec
+cabal-version: >= 1.2
 
-executable: odec
-main-is: odec.hs
-hs-source-dirs: src
+executable odec
+  main-is: odec.hs
+  hs-source-dirs: src
+  build-depends: base >= 4.0.0 && < 4.3, dataenc >= 0.13, directory, filepath, haskell98
+  ghc-options: -Wall
 
-executable: oenc
-main-is: oenc.hs
-hs-source-dirs: src
+executable oenc
+  main-is: oenc.hs
+  hs-source-dirs: src
+  build-depends: base >= 4.0.0 && < 4.3, dataenc >= 0.13, directory, filepath, haskell98
+  ghc-options: -Wall
diff --git a/src/odec.hs b/src/odec.hs
--- a/src/odec.hs
+++ b/src/odec.hs
@@ -17,7 +17,8 @@
 -}
 
 module Main
-    where
+    ( main
+    ) where
 
 import Codec.Binary.DataEncoding
 import Data.Char
@@ -31,6 +32,7 @@
 
 import Paths_omnicodec (version)
 
+ver :: String
 ver = "omnicode decode (odec) " ++ (showVersion version)
     ++ "\nCopyright 2007-2009 Magnus Therning <magnus@therning.org>"
 
@@ -39,14 +41,15 @@
     optDecode :: [String] -> [Maybe Word8],
     optRead :: IO String,
     optWrite :: String -> IO (),
-    fn :: Maybe String  -- needed in case we need to clean up later on
+    optFn :: Maybe String  -- needed in case we need to clean up later on
     }
 
+defaultOptions :: DecOptions
 defaultOptions = DecOptions {
     optDecode = decode' uu . unchop uu,
     optRead = getContents,
     optWrite = putStr,
-    fn = Nothing
+    optFn = Nothing
     }
 
 -- {{{2 Command line
@@ -59,7 +62,10 @@
     ]
 
 -- {{{2 Processing command line
-setOptOutput fn opts = return opts { optWrite = writeFile fn, fn = Just fn }
+setOptOutput :: FilePath -> DecOptions -> IO DecOptions
+setOptOutput fn opts = return opts { optWrite = writeFile fn, optFn = Just fn }
+
+setOptCodec :: String -> DecOptions -> IO DecOptions
 setOptCodec codec opts = case codec of
     "uu" -> return opts { optDecode = decode' uu . unchop uu }
     "xx" -> return opts { optDecode = decode' xx . unchop xx }
@@ -71,8 +77,12 @@
     "b32" -> return opts { optDecode = decode' base32 . unchop base32 }
     "b32h" -> return opts { optDecode = decode' base32Hex . unchop base32Hex }
     "b16" -> return opts { optDecode = decode' base16 . unchop base16 }
+    _ -> error "Unknown encoding."
 
+optShowVersion :: a -> IO DecOptions
 optShowVersion _ = putStrLn ver >> exitWith ExitSuccess
+
+optShowHelp :: DecOptions -> IO DecOptions
 optShowHelp _ = putStrLn (usageInfo "Usage:" options) >> exitWith ExitSuccess
 
 processFileName :: [String] -> IO DecOptions
@@ -87,7 +97,7 @@
 main :: IO ()
 main = do
     args <- getArgs
-    let (actions, nonOpts, msgs) = getOpt RequireOrder options args
+    let (actions, nonOpts, _) = getOpt RequireOrder options args
     opts <- foldl (>>=) (processFileName nonOpts) actions
     CE.catch (optRead opts >>= _decode opts >>= optWrite opts)
-        (\ (CE.SomeException e) -> maybe (return ()) removeFile (fn opts) >> throwIO e)
+        (\ (CE.SomeException e) -> maybe (return ()) removeFile (optFn opts) >> throwIO e)
diff --git a/src/oenc.hs b/src/oenc.hs
--- a/src/oenc.hs
+++ b/src/oenc.hs
@@ -20,17 +20,15 @@
     where
 
 import Codec.Binary.DataEncoding
-import Control.Monad
 import Data.Char
 import Data.Version (showVersion)
 import Data.Word
-import Numeric
 import System
 import System.Console.GetOpt
-import System.FilePath
 
 import Paths_omnicodec (version)
 
+ver :: String
 ver = "omnicode encode (oenc) " ++ (showVersion version)
     ++ "\nCopyright 2007-2009 Magnus Therning <magnus@therning.org>"
 
@@ -41,6 +39,7 @@
     optWrite :: String -> IO ()
     }
 
+defaultOptions :: EncOptions
 defaultOptions = EncOptions {
     optEncode = chop uu 61 . encode uu,
     optRead = getContents,
@@ -56,6 +55,7 @@
     ]
 
 -- {{{2 option actions
+setOptCodec :: String -> EncOptions -> IO EncOptions
 setOptCodec codec opts = case codec of
     "uu" -> return opts { optEncode = chop uu 61 . encode uu }
     "xx" -> return opts { optEncode = chop xx 61 . encode xx }
@@ -67,9 +67,15 @@
     "b32" -> return opts { optEncode = chop base32 60 . encode base32 }
     "b32h" -> return opts { optEncode = chop base32Hex 60 . encode base32Hex }
     "b16" -> return opts { optEncode = chop base16 60 . encode base16 }
+    _ -> error "Unknown encoding."
 
+setOptOutput :: FilePath -> EncOptions -> IO EncOptions
 setOptOutput fn opts = return opts { optWrite = writeFile fn }
+
+optShowVersion :: EncOptions -> IO EncOptions
 optShowVersion _ = putStrLn ver >> exitWith ExitSuccess
+
+optShowHelp :: EncOptions -> IO EncOptions
 optShowHelp _ = putStr (usageInfo "Usage:" options) >> exitWith ExitSuccess
 
 processFileName :: [String] -> IO EncOptions
@@ -84,6 +90,6 @@
 main :: IO ()
 main = do
     args <- getArgs
-    let (actions, nonOpts, msgs) = getOpt RequireOrder options args
+    let (actions, nonOpts, _) = getOpt RequireOrder options args
     opts <- foldl (>>=) (processFileName nonOpts) actions
     optRead opts >>= encode' opts >>= optWrite opts