Haskell multiclipboard

import System.IO
import System.Environment
import System.Hclip

data Hash = Hash {
    key :: String,
    val :: String
}deriving Show

main :: IO()
main = do
    args <- getArgs
    let cmd = args !! 0
    let param = args !! 1
    evalInput cmd param

evalInput cmd param
    | cmd == "cp" = writeToClip param
    | cmd == "sv" = writeToF param
    | cmd == "ls" = listFromfile

writeToF str = do
    k <- getClipboard
    let input = (str ++ " " ++ k)
    file <- openFile "clip.txt" AppendMode
    hClose file

readFromF = do
    file <- openFile "clip.txt" ReadMode
    contents <- hGetContents file
    let singlelines = (lines contents)
    let li = (hashlist singlelines)
    return li

writeToClip str = do
    li <- readFromF
    let result = findByKey li str
    setClipboard result

listFromfile = do
    li <- readFromF
    putStrLn $ prettyprint li

prettyprint :: [Hash] -> String
prettyprint [] = ""
prettyprint (x:xs) = (key x) ++ ":" ++ (val x) ++ "\n" ++ prettyprint xs

hashlist :: [String] -> [Hash]
hashlist [] = []
hashlist (x:xs) = h x : hashlist xs
            where h xs = Hash (head $ words xs) (drop (1 + (length $ head $ words xs)) xs)

findByKey :: [Hash] -> String -> String
findByKey [] str = []
findByKey (x:xs) str
          | (key x) == str = (val x)
          | otherwise = findByKey xs str