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diff --git a/Biz/Language/Bs/Cli.hs b/Biz/Language/Bs/Cli.hs
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+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+module Language.Bs.Cli (
+  run
+) where
+
+import Data.String
+import Data.Text.IO as TIO
+import Language.Bs.Eval -- evalFile :: T.Text -> IO ()
+import Language.Bs.Repl -- Repl.mainLoop :: IO ()
+import Options.Applicative
+import Protolude
+import System.Directory
+
+-- SOURCES
+--http://book.realworldhaskell.org/read/io.html
+-- https://github.com/pcapriotti/optparse-applicative
+-- https://hackage.haskell.org/package/optparse-applicative
+
+runScript ::  FilePath -> IO ()
+runScript fname = do
+  exists <- doesFileExist fname
+  if exists
+  then TIO.readFile fname >>= evalFile fname
+  else TIO.putStrLn "File does not exist."
+
+data LineOpts = UseReplLineOpts | RunScriptLineOpts String
+
+parseLineOpts :: Parser LineOpts
+parseLineOpts = runScriptOpt <|> runReplOpt
+  where
+    runScriptOpt =
+      RunScriptLineOpts <$> strOption (long "script"
+                                       <> short 's'
+                                       <> metavar "SCRIPT"
+                                       <> help "File containing the script you want to run")
+    runReplOpt =
+      UseReplLineOpts <$ flag' () (long "repl"
+                                   <> short 'r'
+                                   <> help "Run as interavtive read/evaluate/print/loop")
+
+schemeEntryPoint :: LineOpts -> IO ()
+schemeEntryPoint UseReplLineOpts = mainLoop --repl
+schemeEntryPoint (RunScriptLineOpts script) = runScript script
+
+run :: IO ()
+run = execParser opts >>= schemeEntryPoint
+  where
+    opts = info (helper <*> parseLineOpts)
+      ( fullDesc
+     <> header "Executable binary for Write You A Scheme v2.0"
+     <> progDesc "contains an entry point for both running scripts and repl" )