diff --git a/markdown-unlit.cabal b/markdown-unlit.cabal
--- a/markdown-unlit.cabal
+++ b/markdown-unlit.cabal
@@ -1,5 +1,5 @@
 name:             markdown-unlit
-version:          0.1.0
+version:          0.2.0
 synopsis:         Literate Haskell support for GitHub's Markdown flavor
 category:         Development
 license:          MIT
diff --git a/src/Text/Markdown/Unlit.hs b/src/Text/Markdown/Unlit.hs
--- a/src/Text/Markdown/Unlit.hs
+++ b/src/Text/Markdown/Unlit.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE CPP #-}
+{-# LANGUAGE CPP, OverloadedStrings #-}
 module Text.Markdown.Unlit (
   run
 , unlit
@@ -34,23 +34,27 @@
   -- #line 1 "label"
   --
   case break (== "-h") args of
-    (xs, ["-h", _, infile, outfile]) ->
-      fmap (unlit $ mkSelector xs) (readFile infile) >>= writeFile outfile
+    (xs, ["-h", fileName, infile, outfile]) ->
+      fmap (unlit fileName $ mkSelector xs) (readFile infile) >>= writeFile outfile
     _ -> do
       name <- getProgName
       hPutStrLn stderr ("usage: " ++ name ++ " [selector] -h label infile outfile")
       exitFailure
     where
-      mkSelector = fromMaybe (Class "haskell") . parseSelector . unwords
+      mkSelector = fromMaybe ("haskell" :&: Not "ignore") . parseSelector . unwords
 
-unlit :: Selector -> String -> String
-unlit selector = unlines . concatMap codeBlockContent . filter (toP selector . codeBlockClasses) . parse
+unlit :: FilePath -> Selector -> String -> String
+unlit fileName selector = unlines . concatMap formatCB . filter (toP selector . codeBlockClasses) . parse
   where
+    formatCB :: CodeBlock -> [String]
+    formatCB cb = ("#line " ++ show (codeBlockStartLine cb) ++ " " ++ show fileName) : codeBlockContent cb
+
     toP :: Selector -> [String] -> Bool
     toP = go
       where
         go s = case s of
           Class c -> elem c
+          Not p   -> not . go p
           a :&: b -> (&&) <$> go a <*> go b
           a :|: b -> (||) <$> go a <*> go b
 
@@ -59,6 +63,7 @@
 
 data Selector
   = Class String
+  | Not Selector
   | Selector :&: Selector
   | Selector :|: Selector
   deriving (Eq, Show)
@@ -68,8 +73,12 @@
   [] -> Nothing
   xs -> (Just . foldr1 (:|:) . map parseAnds) xs
   where
-    parseAnds = foldr1 (:&:) . map Class . split (== '+')
+    parseAnds = foldr1 (:&:) . map parseClass . split (== '+')
 
+    parseClass c = case c of
+      '!':xs -> Not (Class xs)
+      _      -> Class c
+
     -- a copy from https://github.com/sol/string
     split :: (Char -> Bool) -> String -> [String]
     split p = go
@@ -82,30 +91,34 @@
   fromString = Class
 
 data CodeBlock = CodeBlock {
-  codeBlockClasses :: [String]
-, codeBlockContent :: [String]
+  codeBlockClasses   :: [String]
+, codeBlockContent   :: [String]
+, codeBlockStartLine :: Int
 } deriving (Eq, Show)
 
+type Line = (Int, String)
+
 parse :: String -> [CodeBlock]
-parse = go . lines
+parse = go . zip [2..] . lines
   where
-    go :: [String] -> [CodeBlock]
+    go :: [Line] -> [CodeBlock]
     go xs = case break isFence xs of
       (_, [])   -> []
       (_, y:ys) -> case takeCB y ys of
         (cb, rest) -> cb : go rest
 
-    takeCB :: String -> [String] -> (CodeBlock, [String])
-    takeCB fence xs = case break isFence xs of
-      (cb, rest) -> (CodeBlock (parseClasses fence) cb, drop 1 rest)
+    takeCB :: Line -> [Line] -> (CodeBlock, [Line])
+    takeCB (n, fence) xs = case break isFence xs of
+      (cb, rest) -> (CodeBlock (parseClasses fence) (map snd cb) n, drop 1 rest)
 
+    isFence :: Line -> Bool
+    isFence = isPrefixOf "~~~" . snd
+
 parseClasses :: String -> [String]
 parseClasses xs = case dropWhile isSpace . dropWhile (== '~') $ xs of
   '{':ys -> words . replace '.' ' ' . takeWhile (/= '}') $ ys
   _      -> []
 
-isFence :: String -> Bool
-isFence = isPrefixOf "~~~"
 
 replace :: Char -> Char -> String -> String
 replace x sub = map f