In Haskell, I want to read a file and then write to it. Do I need strictness annotation?

Question

Still quite new to Haskell..

I want to read the contents of a file, do something with it possibly involving IO (using putStrLn for now) and then write new contents to th

Answer 1

I think the easiest way to solve this problem is useing strict IO:

import qualified System.IO.Strict as S
main = do
    file <- S.readFile "filename"
    writeFile "filename" file