Hello Awsaf,  you should probably look further into the topic of "IO in Haskell" and "Monads". Then you can use impure functions like readFile (http://hackage.haskell.org/package/base-4.11.1.0/docs/Prelude.html#v:readFil... ) or getArgs (http://hackage.haskell.org/package/base-4.11.1.0/docs/System-Environment.htm...). A naive solution might look like this:    module Main where   import           System.Environment (getArgs)   main = do   (fileName:_) <- getArgs   unsortedList <- read <$> readFile fileName   let sorted = yourMergeSortFunction unsortedList   print sorted -- maybe you like to print your sorted list Best regards, Tobias ----- Nachricht von Awsaf Rahman ---------      Datum: Thu, 5 Jul 2018 22:21:15 +0200        Von: Awsaf Rahman Antwort an: The Haskell-Beginners Mailing List - Discussion of primarily beginner-level topics related to Haskell    Betreff: [Haskell-beginners] Passing a file containing a list as an input         An: beginners@haskell.org

Hello everyone!    I am really struggling with Haskell I/O.    I have written a mergesort program and as an input to that program I want to use a file containing a list of 1000 integers. Let's say the contents of the file look like this   [120, 400, 500 , 20, 100 ..]    How can I achieve that? I am trying to write a main function that takes the file as an input and passes the list to my mergesort function..    Regards Awsaf Rahman

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