title: How to import ‘System.IO.Strict’? (HASKELL)
body: <p>I am trying to open a file and move the first line last, like so:</p>
  <pre><code>-- Moves the first line in a file to the end of the file (first line becomes last line)
  flyttLn :: FilePath -&gt; IO ()
  flyttLn fn = do
      fh &lt;- openFile fn ReadMode
      content &lt;- hGetContents fh
      --putStrLn content 
      let
          (l1:rest) = lines content
          newContent = unlines (rest++[l1])
      hClose fh
      fh2 &lt;- openFile fn WriteMode
      hPutStr fh2 newContent
      hClose fh2
  </code></pre>
  <p>Which gives me an error because of lazy-evaluation. So based of <a href="https://stackoverflow.com/questions/2527271/in-haskell-i-want-to-read-a-file-and-then-write-to-it-do-i-need-strictness-ann/2530948">this</a> question, I first tried to print the contents of the file, and then re-write them. Which works, except I don't want to print the whole file in the terminal. So I tried to import <code>System.IO.Strict</code> like so</p>
  <pre><code>import qualified System.IO.Strict as SIO
  </code></pre>
  <p>But VS Code gives me an error saying</p>
  <pre><code>Could not find module ‘System.IO.Strict’
  It is not a module in the current program, or in any known package.not found
  </code></pre>
  <p>I have tried to find similar problems, but I only found <a href="https://stackoverflow.com/questions/7265550/haskell-could-not-find-module-system">this</a> question, and it didn't help me solve my problem here.</p>
  <p>How can I properly, open a file and edit its content, without having to print the whole file in the terminal? How do I import System.IO.Strict correctly?</p>