diff --git a/Main.hs b/Main.hs
--- a/Main.hs
+++ b/Main.hs
@@ -25,13 +25,14 @@
 import qualified Options.Applicative as O
 import qualified Text.CSV as CSV
 
-data Options = Options { jsonExpr :: String, outputMode :: OutputMode } deriving Show
+data Options = Options { jsonExpr :: String, arrayDelim :: String, outputMode :: OutputMode } deriving Show
 
 data OutputMode = TSVOutput { delimiter :: String } | CSVOutput deriving (Show)
 
 parseOpts :: O.Parser Options
 parseOpts = Options 
   <$> O.argument O.str (O.metavar "FIELDS")
+  <*> O.strOption (O.metavar "ARRAY-DELIM" <> O.value "," <> O.short 'a' <> O.help "concatentated array elem delimiter. Default to comma")
   <*> ((O.flag' CSVOutput (O.short 'c' <> O.long "csv" <> O.help "output CSV"))
        <|> (TSVOutput <$> (O.strOption (O.metavar "DELIM" <> O.value "\t" <> O.short 'd' <> O.help "output field delimiter. Defaults to tab"))))
 
@@ -39,15 +40,16 @@
           (O.fullDesc <> O.progDesc "Transform JSON objects to TSV" <> O.header "jsontsv")
 
 main = do
-  Options expr mode <- O.execParser opts
+  Options expr arrayDelim mode <- O.execParser opts
   x <- BL.getContents 
   let xs :: [Value]
       xs = decodeStream x
-  let ks' = parseKeyPath $ T.pack expr
+      ks' = parseKeyPath $ T.pack expr
+      arrayDelim' = T.pack arrayDelim
   -- Prelude.putStrLn $ "key Paths " ++ show ks'
   case mode of 
-    TSVOutput delim -> mapM_ (TL.putStrLn . B.toLazyText . evalToLineBuilder delim ks') xs
-    CSVOutput -> Prelude.putStrLn . CSV.printCSV $ map (map T.unpack . evalToList ks') $  xs
+    TSVOutput delim -> mapM_ (TL.putStrLn . B.toLazyText . evalToLineBuilder arrayDelim' delim ks') xs
+    CSVOutput -> Prelude.putStrLn . CSV.printCSV $ map (map T.unpack . evalToList arrayDelim' ks') $  xs
 
 decodeStream :: (FromJSON a) => BL.ByteString -> [a]
 decodeStream bs = case decodeWith json bs of
@@ -86,44 +88,47 @@
 type KeyPath = [Key]
 data Key = Key Text | Index Int deriving (Eq, Show)
 
-evalToLineBuilder :: String -> [KeyPath] -> Value -> B.Builder 
-evalToLineBuilder delim ks v = mconcat $ intersperse (B.fromText . T.pack $ delim) $  map (flip evalToBuilder v) ks
+evalToLineBuilder :: Text -> String -> [KeyPath] -> Value -> B.Builder 
+evalToLineBuilder arrayDelim delim ks v = 
+    mconcat $ intersperse (B.fromText . T.pack $ delim) $  map (flip (evalToBuilder arrayDelim) v) ks
 
-evalToList :: [KeyPath] -> Value -> [Text]
-evalToList ks v = map (flip evalToText v) ks
+type ArrayDelimiter = Text
 
-evalToBuilder :: KeyPath -> Value -> B.Builder
-evalToBuilder k v = valToBuilder $ evalKeyPath k v
+evalToList :: Text -> [KeyPath] -> Value -> [Text]
+evalToList arrayDelim ks v = map (flip (evalToText arrayDelim) v) ks
 
-evalToText :: KeyPath -> Value -> Text
-evalToText k v = valToText $ evalKeyPath k v
+evalToBuilder :: ArrayDelimiter -> KeyPath -> Value -> B.Builder
+evalToBuilder d k v = valToBuilder $ evalKeyPath d k v
 
+evalToText :: ArrayDelimiter -> KeyPath -> Value -> Text
+evalToText d k v = valToText $ evalKeyPath d k v
+
 -- evaluates the a JS key path against a Value context to a leaf Value
-evalKeyPath :: KeyPath -> Value -> Value
-evalKeyPath [] x@(String _) = x
-evalKeyPath [] x@Null = x
-evalKeyPath [] x@(Number _) = x
-evalKeyPath [] x@(Bool _) = x
-evalKeyPath [] x@(Object _) = x
-evalKeyPath [] x@(Array v) = 
+evalKeyPath :: ArrayDelimiter -> KeyPath -> Value -> Value
+evalKeyPath d [] x@(String _) = x
+evalKeyPath d [] x@Null = x
+evalKeyPath d [] x@(Number _) = x
+evalKeyPath d [] x@(Bool _) = x
+evalKeyPath d [] x@(Object _) = x
+evalKeyPath d [] x@(Array v) = 
           let vs = V.toList v
-              xs = intersperse "," $ map (evalToText []) vs
+              xs = intersperse d $ map (evalToText d []) vs
           in String . mconcat $ xs
-evalKeyPath (Key key:ks) (Object s) = 
+evalKeyPath d (Key key:ks) (Object s) = 
     case (HM.lookup key s) of
-        Just x          -> evalKeyPath ks x
+        Just x          -> evalKeyPath d ks x
         Nothing -> Null
-evalKeyPath (Index idx:ks) (Array v) = 
+evalKeyPath d (Index idx:ks) (Array v) = 
       let e = (V.!?) v idx
       in case e of 
-        Just e' -> evalKeyPath ks e'
+        Just e' -> evalKeyPath d ks e'
         Nothing -> Null
 -- traverse array elements with additional keys
-evalKeyPath ks@(Key key:_) (Array v) = 
+evalKeyPath d ks@(Key key:_) (Array v) = 
       let vs = V.toList v
-      in String . mconcat . intersperse "," $ map (evalToText ks) vs
-evalKeyPath ((Index _):_) _ = Null
-evalKeyPath _ _ = Null
+      in String . mconcat . intersperse d $ map (evalToText d ks) vs
+evalKeyPath _ ((Index _):_) _ = Null
+evalKeyPath _ _ _ = Null
 
 valToBuilder :: Value -> B.Builder
 valToBuilder (String x) = B.fromText x
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -14,28 +14,6 @@
   "title": "Terminator 2: Judgement Day",
   "year": 1991,
   "stars": [
-    "Arnold Schwarzenegger",
-    "Linda Hamilton"
-  ],
-  "ratings": {
-    "imdb": 8.5
-  }
-}
-{
-  "title": "Interstellar",
-  "year": 2014,
-  "stars": [
-    "Matthew McConaughey",
-    "Anne Hathaway"
-  ],
-  "ratings": {
-    "imdb": 8.9
-  }
-}
-{
-  "title": "Terminator 2: Judgement Day",
-  "year": 1991,
-  "stars": [
     {
       "name": "Arnold Schwarzenegger"
     },
@@ -102,11 +80,12 @@
 ```
 jsontsv
 
-Usage: jsontsv FIELDS ([-c|--csv] | [-d DELIM])
+Usage: jsontsv FIELDS [-a ARRAY-DELIM] ([-c|--csv] | [-d DELIM])
   Transform JSON objects to TSV
 
 Available options:
   -h,--help                Show this help text
+  -a ARRAY-DELIM           concatentated array element delimiter. Defaults to comma
   -c,--csv                 output CSV
   -d DELIM                 output field delimiter. Defaults to tab
 ```
@@ -139,7 +118,8 @@
 * Strings and numbers are copied to output.
 * Boolean values are output as `t` or `f`.
 * null is printed as `null`
-* If the leaf value is an array, it is concatenated into a single comma-separated string
+* If the leaf value is an array, it is concatenated into a single
+  comma-separated string. The delimiter can be changed with the `-a` option.
 
 ## Performing post-processing on field values
 
@@ -147,6 +127,7 @@
 
 ## Known alternatives 
 
-* [jsawk](https://github.com/micha/jsawk) 
+* [jsawk](https://github.com/micha/jsawk) Jsawk is like awk, but for JSON. (nodejs)
 * [jq][jq]
-* [jsoncsv](https://github.com/gradus/jsoncsv)
+* [jsoncsv](https://github.com/gradus/jsoncsv) a json to csv library in javascript/coffeescript
+* [json](https://github.com/konklone/json) A free, in-browser JSON to CSV converter.
diff --git a/jsontsv.cabal b/jsontsv.cabal
--- a/jsontsv.cabal
+++ b/jsontsv.cabal
@@ -2,7 +2,7 @@
 --  see http://haskell.org/cabal/users-guide/
 
 name:                jsontsv
-version:             0.1.2.0
+version:             0.1.3.0
 synopsis:            JSON to TSV transformer
 homepage:            https://github.com/danchoi/jsontsv
 description:         Transforms JSON into tab-separated line-oriented output, for easier processing in Unix-style pipelines.