baabaa.hs

import System.IO
import Data.Char
main = do
    contents <- readFile "baabaa.txt"
    writeFile "baabaacaps.txt" (map toUpper contents)

baabaa.txt

Baa, baa, black sheep,
Have you any wool?
Yes, sir, yes, sir,
Three bags full;

baabaacaps.txt

BAA, BAA, BLACK SHEEP,
HAVE YOU ANY WOOL?
YES, SIR, YES, SIR,
THREE BAGS FULL;