Stable version 0.3.2

This release is dedicated to knirch, mcandre, Dridi,
ptman, pihentagy, Riviera, and everyone else who keeps
submitting bug reports and feature suggestions!

README

@@ -1,44 +0,0 @@
-ShellCheck - A shell script static analysis tool
-http://www.vidarholen.net/contents/shellcheck
-
-Copyright 2012, Vidar 'koala_man' Holen
-Licensed under the GNU Affero General Public License, v3
-
-The goals of ShellCheck are:
-
-  - To point out and clarify typical beginner's syntax issues,
-    that causes a shell to give cryptic error messages.
-
-  - To point out and clarify typical intermediate level semantic problems,
-    that causes a shell to behave strangely and counter-intuitively.
-
-  - To point out subtle caveats, corner cases and pitfalls, that may cause an
-    advanced user's otherwise working script to fail under future circumstances.
-
-ShellCheck is written in Haskell, and requires GHC, Parsec3 and Text.Regex. 
-To build the JSON interface and run the unit tests, it also requires QuickCheck2 and JSON.
-
-On Fedora, these can be installed with:
-  yum install cabal-install ghc ghc-parsec-devel ghc-QuickCheck-devel ghc-json-devel ghc-regex-compat-devel
-
-On Ubuntu and similar, use:
-  apt-get install ghc libghc-parsec3-dev libghc-json-dev libghc-regex-compat-dev libghc-quickcheck2-dev cabal-install
-
-For older releases, you may have to use:
-  apt-get install ghc6 libghc6-parsec3-dev libghc6-quickcheck2-dev libghc6-json-dev libghc-regex-compat-dev cabal-install
-
-On Mac OS X with homebrew (http://brew.sh/), use:
-  brew install cabal-install
-
-On Mac OS X with MacPorts (http://www.macports.org/), use:
-  port install hs-cabal-install
-
-Executables can be built with cabal. Tests currently still rely on a Makefile.
-
-Install:
-  cabal install
-
-  which shellcheck
-  ~/.cabal/bin/shellcheck
-
-Happy ShellChecking!

README.md

@@ -0,0 +1,68 @@
+# ShellCheck - A shell script static analysis tool
+
+http://www.shellcheck.net
+
+Copyright 2012-2014, Vidar 'koala_man' Holen
+Licensed under the GNU Affero General Public License, v3
+
+The goals of ShellCheck are:
+
+  - To point out and clarify typical beginner's syntax issues,
+    that causes a shell to give cryptic error messages.
+
+  - To point out and clarify typical intermediate level semantic problems,
+    that causes a shell to behave strangely and counter-intuitively.
+
+  - To point out subtle caveats, corner cases and pitfalls, that may cause an
+    advanced user's otherwise working script to fail under future circumstances.
+
+ShellCheck requires at least 1 GB of RAM to compile. Executables can be built with cabal. Tests currently still rely on a Makefile.
+
+
+## Building with Cabal
+
+Make sure cabal is installed. On Debian based distros:
+
+    apt-get install cabal-install
+
+On Fedora:
+
+    yum install cabal-install
+
+On Mac OS X with homebrew (http://brew.sh/):
+
+    brew install cabal-install
+
+On Mac OS X with MacPorts (http://www.macports.org/):
+
+    port install hs-cabal-install
+
+With cabal installed, cd to the shellcheck source directory and:
+
+    $ cabal install
+    ...
+    $ which shellcheck
+    ~/.cabal/bin/shellcheck
+
+
+## Building with Make
+
+ShellCheck is written in Haskell, and requires GHC, Parsec3, JSON and
+Text.Regex. To run the unit tests, it also requires QuickCheck2.
+
+On Fedora, these can be installed with:
+
+    yum install ghc ghc-parsec-devel ghc-QuickCheck-devel \
+      ghc-json-devel ghc-regex-compat-devel
+
+On Ubuntu and similar, use:
+
+    apt-get install ghc libghc-parsec3-dev libghc-json-dev \
+      libghc-regex-compat-dev libghc-quickcheck2-dev
+
+To build and run the tests, cd to the shellcheck source directory and:
+
+    $ make
+
+
+Happy ShellChecking!

ShellCheck.cabal

@@ -1,6 +1,6 @@
 Name:             ShellCheck
 -- Must also be updated in ShellCheck/Data.hs :
-Version:          0.3.1
+Version:          0.3.2
 Synopsis:         Shell script analysis tool
 License:          OtherLicense
 License-file:     LICENSE
@@ -9,7 +9,7 @@ Author:           Vidar Holen
 Maintainer:       vidar@vidarholen.net
 Homepage:         http://www.shellcheck.net/
 Build-Type:       Simple
-Cabal-Version:    >= 1.6
+Cabal-Version:    >= 1.8
 Bug-reports:      https://github.com/koalaman/shellcheck/issues
 Description:
   The goals of ShellCheck are:
@@ -28,8 +28,29 @@ source-repository head
     location: git://github.com/koalaman/shellcheck.git
 
 library
-    build-depends: base >= 4, base < 5, parsec, containers, regex-compat, mtl, directory, json
-    exposed-modules: ShellCheck.AST, ShellCheck.Data, ShellCheck.Parser, ShellCheck.Analytics, ShellCheck.Simple
+    build-depends:
+      base >= 4 && < 5,
+      containers,
+      directory,
+      json,
+      mtl,
+      parsec,
+      regex-compat
+    exposed-modules:
+      ShellCheck.Analytics
+      ShellCheck.AST
+      ShellCheck.Data
+      ShellCheck.Parser
+      ShellCheck.Simple
 
 executable shellcheck
+    build-depends:
+      ShellCheck,
+      base >= 4 && < 5,
+      containers,
+      directory,
+      json,
+      mtl,
+      parsec,
+      regex-compat
     main-is: shellcheck.hs

ShellCheck/AST.hs

@@ -102,7 +102,7 @@ data Token =
     | T_NormalWord Id [Token]
     | T_OR_IF Id
     | T_OrIf Id (Token) (Token)
-    | T_Pipeline Id [Token]
+    | T_Pipeline Id [Token] [Token] -- [Pipe separators] [Commands]
     | T_ProcSub Id String [Token]
     | T_Rbrace Id
     | T_Redirecting Id [Token] Token
@@ -120,6 +120,7 @@ data Token =
     | T_While Id
     | T_WhileExpression Id [Token] [Token]
     | T_Annotation Id [Annotation] Token
+    | T_Pipe Id String
     deriving (Show)
 
 data Annotation = DisableComment Integer deriving (Show, Eq)
@@ -128,12 +129,12 @@ data ConditionType = DoubleBracket | SingleBracket deriving (Show, Eq)
 -- I apologize for nothing!
 lolHax s = Re.subRegex (Re.mkRegex "(Id [0-9]+)") (show s) "(Id 0)"
 instance Eq Token where
-    (==) a b = (lolHax a) == (lolHax b)
+    (==) a b = lolHax a == lolHax b
 
 
 analyze :: Monad m => (Token -> m ()) -> (Token -> m ()) -> (Token -> Token) -> Token -> m Token
-analyze f g i t =
-    round t
+analyze f g i =
+    round
   where
     round t = do
         f t
@@ -182,7 +183,7 @@ analyze f g i t =
         b <- round cmd
         return $ T_Redirecting id a b
     delve (T_SimpleCommand id vars cmds) = dll vars cmds $ T_SimpleCommand id
-    delve (T_Pipeline id l) = dl l $ T_Pipeline id
+    delve (T_Pipeline id l1 l2) = dll l1 l2 $ T_Pipeline id
     delve (T_Banged id l) = d1 l $ T_Banged id
     delve (T_AndIf id t u) = d2 t u $ T_AndIf id
     delve (T_OrIf id t u) = d2 t u $ T_OrIf id
@@ -297,7 +298,7 @@ getId t = case t of
         T_Array id _  -> id
         T_Redirecting id _ _  -> id
         T_SimpleCommand id _ _  -> id
-        T_Pipeline id _  -> id
+        T_Pipeline id _ _  -> id
         T_Banged id _  -> id
         T_AndIf id _ _ -> id
         T_OrIf id _ _ -> id
@@ -337,17 +338,18 @@ getId t = case t of
         T_DollarDoubleQuoted id _ -> id
         T_DollarBracket id _ -> id
         T_Annotation id _ _ -> id
+        T_Pipe id _ -> id
 
 blank :: Monad m => Token -> m ()
 blank = const $ return ()
-doAnalysis f t = analyze f blank id t
-doStackAnalysis startToken endToken t = analyze startToken endToken id t
-doTransform i t = runIdentity $ analyze blank blank i t
+doAnalysis f = analyze f blank id
+doStackAnalysis startToken endToken = analyze startToken endToken id
+doTransform i = runIdentity . analyze blank blank i
 
 isLoop t = case t of
-        T_WhileExpression _ _ _  -> True
-        T_UntilExpression _ _ _  -> True
-        T_ForIn _ _ _ _  -> True
-        T_ForArithmetic _ _ _ _ _ -> True
-        T_SelectIn _ _ _ _  -> True
+        T_WhileExpression {} -> True
+        T_UntilExpression {} -> True
+        T_ForIn {} -> True
+        T_ForArithmetic {} -> True
+        T_SelectIn {}  -> True
         _ -> False

ShellCheck/Data.hs

@@ -1,6 +1,6 @@
 module ShellCheck.Data where
 
-shellcheckVersion = "0.3.1"  -- Must also be updated in ShellCheck.cabal
+shellcheckVersion = "0.3.2"  -- Must also be updated in ShellCheck.cabal
 
 internalVariables = [
     -- Generic

ShellCheck/Parser.hs

@@ -46,14 +46,18 @@ tokenDelimiter = oneOf "&|;<> \t\n\r" <|> nbsp
 quotableChars = "|&;<>()\\ '\t\n\r\xA0" ++ doubleQuotableChars
 quotable = nbsp <|> unicodeDoubleQuote <|> oneOf quotableChars
 bracedQuotable = oneOf "}\"$`'"
-doubleQuotableChars = "\"$`\x201C\x201D"
+doubleQuotableChars = "\"$`" ++ unicodeDoubleQuoteChars
 doubleQuotable = unicodeDoubleQuote <|> oneOf doubleQuotableChars
 whitespace = oneOf " \t\n" <|> carriageReturn <|> nbsp
 linewhitespace = oneOf " \t" <|> nbsp
 
+suspectCharAfterQuotes = variableChars <|> char '%'
+
 extglobStartChars = "?*@!+"
 extglobStart = oneOf extglobStartChars
 
+unicodeDoubleQuoteChars = "\x201C\x201D\x2033\x2036"
+
 prop_spacing = isOk spacing "  \\\n # Comment"
 spacing = do
     x <- many (many1 linewhitespace <|> (try $ string "\\\n"))
@@ -78,7 +82,7 @@ allspacingOrFail = do
 
 unicodeDoubleQuote = do
     pos <- getPosition
-    char '\x201C' <|> char '\x201D'
+    oneOf unicodeDoubleQuoteChars
     parseProblemAt pos WarningC 1015 "This is a unicode double quote. Delete and retype it."
     return '"'
 
@@ -313,9 +317,11 @@ readConditionContents single = do
         when (endedWith "]" x) $ do
             parseProblemAt pos ErrorC 1020 $
                 "You need a space before the " ++ (if single then "]" else "]]") ++ "."
+            fail "Missing space before ]"
         when (single && endedWith ")" x) $ do
             parseProblemAt pos ErrorC 1021 $
                 "You need a space before the \\)"
+            fail "Missing space before )"
         disregard spacing
         return x
       where endedWith str (T_NormalWord id s@(_:_)) =
@@ -327,6 +333,7 @@ readConditionContents single = do
         id <- getNextId
         x <- try (string "&&" <|> string "-a")
         softCondSpacing
+        skipLineFeeds
         return $ TC_And id typ x
 
     readCondOrOp = do
@@ -334,6 +341,7 @@ readConditionContents single = do
         id <- getNextId
         x <- try (string "||" <|> string "-o")
         softCondSpacing
+        skipLineFeeds
         return $ TC_Or id typ x
 
     readCondNoaryOrBinary = do
@@ -412,7 +420,17 @@ readConditionContents single = do
             str <- string "|"
             return $ T_Literal id str
 
-    readCondTerm = readCondNot <|> readCondExpr
+    skipLineFeeds = do
+        pos <- getPosition
+        spacing <- allspacing
+        when (single  && '\n' `elem` spacing) $
+            parseProblemAt pos ErrorC 1080 "In [ ] you need \\ before line feeds."
+
+    readCondTerm = do
+        term <- readCondNot <|> readCondExpr
+        skipLineFeeds
+        return term
+
     readCondNot = do
         id <- getNextId
         char '!'
@@ -611,6 +629,9 @@ prop_readCondition6 = isOk readCondition "[[ $c =~ ^[yY]$ ]]"
 prop_readCondition7 = isOk readCondition "[[ ${line} =~ ^[[:space:]]*# ]]"
 prop_readCondition8 = isOk readCondition "[[ $l =~ ogg|flac ]]"
 prop_readCondition9 = isOk readCondition "[ foo -a -f bar ]"
+prop_readCondition10= isOk readCondition "[[ a == b \n || c == d ]]"
+prop_readCondition11= isOk readCondition "[[ a == b || \n c == d ]]"
+prop_readCondition12= isWarning readCondition "[ a == b \n -o c == d ]"
 readCondition = called "test expression" $ do
     opos <- getPosition
     id <- getNextId
@@ -739,17 +760,29 @@ readProcSub = called "process substitution" $ do
 prop_readSingleQuoted = isOk readSingleQuoted "'foo bar'"
 prop_readSingleQuoted2 = isWarning readSingleQuoted "'foo bar\\'"
 prop_readsingleQuoted3 = isWarning readSingleQuoted "\x2018hello\x2019"
+prop_readSingleQuoted4 = isWarning readNormalWord "'it's"
+prop_readSingleQuoted5 = isWarning readSimpleCommand "foo='bar\ncow 'arg"
+prop_readSingleQuoted6 = isOk readSimpleCommand "foo='bar cow 'arg"
 readSingleQuoted = called "single quoted string" $ do
     id <- getNextId
+    startPos <- getPosition
     singleQuote
     s <- readSingleQuotedPart `reluctantlyTill` singleQuote
-    pos <- getPosition
+    let string = concat s
+    endPos <- getPosition
     singleQuote <?> "end of single quoted string"
 
-    let string = concat s
-    return (T_SingleQuoted id string) `attempting` do
-        x <- lookAhead anyChar
-        when (isAlpha x && not (null string) && isAlpha (last string)) $ parseProblemAt pos WarningC 1011 "This apostrophe terminated the single quoted string!"
+    optional $ do
+        c <- try . lookAhead $ suspectCharAfterQuotes <|> oneOf "'"
+        if (not (null string) && isAlpha c && isAlpha (last string))
+          then
+            parseProblemAt endPos WarningC 1011 $
+                "This apostrophe terminated the single quoted string!"
+          else
+            when ('\n' `elem` string && not ("\n" `isPrefixOf` string)) $
+                suggestForgotClosingQuote startPos endPos "single quoted string"
+
+    return (T_SingleQuoted id string)
 
 readSingleQuotedLiteral = do
     singleQuote
@@ -763,13 +796,24 @@ readSingleQuotedPart =
 
 prop_readBackTicked = isOk readBackTicked "`ls *.mp3`"
 prop_readBackTicked2 = isOk readBackTicked "`grep \"\\\"\"`"
+prop_readBackTicked3 = isWarning readBackTicked "´grep \"\\\"\"´"
+prop_readBackTicked4 = isOk readBackTicked "`echo foo\necho bar`"
+prop_readBackTicked5 = isOk readSimpleCommand "echo `foo`bar"
+prop_readBackTicked6 = isWarning readSimpleCommand "echo `foo\necho `bar"
 readBackTicked = called "backtick expansion" $ do
     id <- getNextId
-    pos <- getPosition
-    char '`'
+    startPos <- getPosition
+    backtick
     subStart <- getPosition
-    subString <- readGenericLiteral "`"
-    char '`'
+    subString <- readGenericLiteral "`´"
+    endPos <- getPosition
+    backtick
+
+    optional $ do
+        c <- try . lookAhead $ suspectCharAfterQuotes
+        when ('\n' `elem` subString && not ("\n" `isPrefixOf` subString)) $ do
+            suggestForgotClosingQuote startPos endPos "backtick expansion"
+
     -- Result positions may be off due to escapes
     result <- subParse subStart readCompoundList (unEscape subString)
     return $ T_Backticked id result
@@ -778,6 +822,12 @@ readBackTicked = called "backtick expansion" $ do
     unEscape ('\\':x:rest) | x `elem` "$`\\" = x : unEscape rest
     unEscape ('\\':'\n':rest) = unEscape rest
     unEscape (c:rest) = c : unEscape rest
+    backtick =
+      disregard (char '`') <|> do
+         pos <- getPosition
+         char '´'
+         parseProblemAt pos ErrorC 1077 $
+            "For command expansion, the tick should slant left (` vs ´)."
 
 subParse pos parser input = do
     lastPosition <- getPosition
@@ -792,12 +842,31 @@ subParse pos parser input = do
 prop_readDoubleQuoted = isOk readDoubleQuoted "\"Hello $FOO\""
 prop_readDoubleQuoted2 = isOk readDoubleQuoted "\"$'\""
 prop_readDoubleQuoted3 = isWarning readDoubleQuoted "\x201Chello\x201D"
+prop_readDoubleQuoted4 = isWarning readSimpleCommand "\"foo\nbar\"foo"
+prop_readDoubleQuoted5 = isOk readSimpleCommand "lol \"foo\nbar\" etc"
 readDoubleQuoted = called "double quoted string" $ do
     id <- getNextId
+    startPos <- getPosition
     doubleQuote
     x <- many doubleQuotedPart
+    endPos <- getPosition
     doubleQuote <?> "end of double quoted string"
+    optional $ do
+        try . lookAhead $ suspectCharAfterQuotes <|> oneOf "$\""
+        when (any hasLineFeed x && not (startsWithLineFeed x)) $
+            suggestForgotClosingQuote startPos endPos "double quoted string"
     return $ T_DoubleQuoted id x
+  where
+    startsWithLineFeed ((T_Literal _ ('\n':_)):_) = True
+    startsWithLineFeed _ = False
+    hasLineFeed (T_Literal _ str) | '\n' `elem` str = True
+    hasLineFeed _ = False
+
+suggestForgotClosingQuote startPos endPos name = do
+    parseProblemAt startPos WarningC 1078 $
+        "Did you forget to close this " ++ name ++ "?"
+    parseProblemAt endPos InfoC 1079 $
+        "This is actually an end quote, but due to next char it looks suspect."
 
 doubleQuotedPart = readDoubleLiteral <|> readDoubleQuotedDollar <|> readBackTicked
 
@@ -1325,13 +1394,25 @@ transformWithSeparator i _  = id
 
 readPipeSequence = do
     id <- getNextId
-    list <- readCommand `sepBy1` (readPipe `thenSkip` (spacing >> readLineBreak))
+    (cmds, pipes) <- sepBy1WithSeparators readCommand
+                        (readPipe `thenSkip` (spacing >> readLineBreak))
     spacing
-    return $ T_Pipeline id list
+    return $ T_Pipeline id pipes cmds
+  where
+    sepBy1WithSeparators p s = do
+        let elems = p >>= \x -> return ([x], [])
+        let seps = do
+            separator <- s
+            return $ \(a,b) (c,d) -> (a++c, b ++ d ++ [separator])
+        elems `chainl1` seps
 
 readPipe = do
     notFollowedBy2 g_OR_IF
-    char '|' `thenSkip` spacing
+    id <- getNextId
+    char '|'
+    qualifier <- string "&" <|> return ""
+    spacing
+    return $ T_Pipe id ('|':qualifier)
 
 readCommand = (readCompoundCommand <|> readSimpleCommand)
 
@@ -1682,7 +1763,8 @@ readAssignmentWord = try $ do
     if space == "" && space2 /= ""
       then do
         when (variable /= "IFS") $
-            parseNoteAt pos InfoC 1007 $ "Note that 'var= value' (with space after equals sign) is similar to 'var=\"\"; value'."
+            parseNoteAt pos WarningC 1007
+                "Remove space after = if trying to assign a value (for empty string, use var='' ... )."
         value <- readEmptyLiteral
         return $ T_Assignment id op variable index value
       else do
@@ -1729,16 +1811,24 @@ redirToken c t = try $ do
     notFollowedBy2 $ char '('
     return $ t id
 
-tryWordToken s t = tryParseWordToken (string s) t `thenSkip` spacing
-tryParseWordToken parser t = try $ do
+tryWordToken s t = tryParseWordToken s t `thenSkip` spacing
+tryParseWordToken keyword t = try $ do
     id <- getNextId
-    parser
+    str <- anycaseString keyword
     optional (do
         try . lookAhead $ char '['
         parseProblem ErrorC 1069 "You need a space before the [.")
     try $ lookAhead (keywordSeparator)
+    when (str /= keyword) $
+        parseProblem ErrorC 1081 $
+            "Scripts are case sensitive. Use '" ++ keyword ++ "', not '" ++ str ++ "'."
     return $ t id
 
+anycaseString str =
+    mapM anycaseChar str
+  where
+    anycaseChar c = char (toLower c) <|> char (toUpper c)
+
 g_AND_IF = tryToken "&&" T_AND_IF
 g_OR_IF = tryToken "||" T_OR_IF
 g_DSEMI = tryToken ";;" T_DSEMI

shellcheck.hs

@@ -69,7 +69,7 @@ parseArguments argv =
             return $ Just (opts, files)
 
         (_, _, errors) -> do
-            printErr $ (concat errors) ++ "\n" ++ usageInfo header options
+            printErr $ concat errors ++ "\n" ++ usageInfo header options
             exitWith syntaxFailure
 
 formats = Map.fromList [
@@ -84,7 +84,7 @@ forTty options files = do
     return $ and output
   where
     clear = ansi 0
-    ansi n = "\x1B[" ++ (show n) ++ "m"
+    ansi n = "\x1B[" ++ show n ++ "m"
 
     colorForLevel "error" = 31 -- red
     colorForLevel "warning" = 33 -- yellow
@@ -94,7 +94,8 @@ forTty options files = do
     colorForLevel "source" = 0 -- none
     colorForLevel _ = 0 -- none
 
-    colorComment level comment = (ansi $ colorForLevel level) ++ comment ++ clear
+    colorComment level comment =
+        ansi (colorForLevel level) ++ comment ++ clear
 
     doFile path = do
         contents <- readContents path
@@ -112,15 +113,17 @@ forTty options files = do
                             then ""
                             else fileLines !! (lineNum - 1)
             putStrLn ""
-            putStrLn $ colorFunc "message" ("In " ++ filename ++" line " ++ (show $ lineNum) ++ ":")
+            putStrLn $ colorFunc "message"
+                ("In " ++ filename ++" line " ++ show lineNum ++ ":")
             putStrLn (colorFunc "source" line)
-            mapM (\c -> putStrLn (colorFunc (scSeverity c) $ cuteIndent c)) x
+            mapM_ (\c -> putStrLn (colorFunc (scSeverity c) $ cuteIndent c)) x
             putStrLn ""
           ) groups
         return $ null comments
 
     cuteIndent comment =
-        (replicate ((scColumn comment) - 1) ' ') ++ "^-- " ++ (code $ scCode comment) ++ ": " ++ (scMessage comment)
+        replicate (scColumn comment - 1) ' ' ++
+            "^-- " ++ code (scCode comment) ++ ": " ++ scMessage comment
 
     code code = "SC" ++ (show code)
 
@@ -131,7 +134,7 @@ forTty options files = do
 -- This totally ignores the filenames. Fixme?
 forJson options files = do
     comments <- liftM concat $ mapM (commentsFor options) files
-    putStrLn $ encodeStrict $ comments
+    putStrLn $ encodeStrict comments
     return . null $ comments
 
 -- Mimic GCC "file:line:col: (error|warning|note): message" format
@@ -178,8 +181,8 @@ forCheckstyle options files = do
     severity "warning" = "warning"
     severity _ = "info"
     attr s v = concat [ s, "='", escape v, "' " ]
-    escape msg = concatMap escape' msg
-    escape' c = if isOk c then [c] else "&#" ++ (show $ ord c) ++ ";"
+    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 [
@@ -226,7 +229,7 @@ makeNonVirtual comments contents =
     real (_:rest) r v target = real rest (r+1) (v+1) target
 
 getOption [] _ = Nothing
-getOption ((Flag var val):_) name | name == var = return val
+getOption (Flag var val:_) name | name == var = return val
 getOption (_:rest) flag = getOption rest flag
 
 getOptions options name =
@@ -247,8 +250,8 @@ getExclusions options =
     in
         map (Prelude.read . clean) elements :: [Int]
 
-excludeCodes codes comments =
-    filter (not . hasCode) comments
+excludeCodes codes =
+    filter (not . hasCode)
   where
     hasCode c = scCode c `elem` codes
 
@@ -265,7 +268,7 @@ main = do
     exitWith code
 
 process Nothing = return False
-process (Just (options, files)) = do
+process (Just (options, files)) =
   let format = fromMaybe "tty" $ getOption options "format" in
     case Map.lookup format formats of
         Nothing -> do
@@ -281,11 +284,9 @@ verifyOptions opts files = do
     when (isJust $ getOption opts "version") printVersionAndExit
 
     let shell = getOption opts "shell" in
-        if isNothing shell
-        then return ()
-        else when (isNothing $ shell >>= shellForExecutable) $ do
-                printErr $ "Unknown shell: " ++ (fromJust shell)
-                exitWith supportFailure
+        when (isJust shell && isNothing (shell >>= shellForExecutable)) $ do
+            printErr $ "Unknown shell: " ++ (fromJust shell)
+            exitWith supportFailure
 
     when (null files) $ do
         printErr "No files specified.\n"