mk_user :: NewUser -> ShIO Text
mk_user user =
  run_sudo "addUser" [login user, "--gecos", firstName user <> " " <> lastName user]
run_sudo :: Text -> [Text] -> ShIO Text
run_sudo cmd args = run "/usr/bin/sudo" (cmd:args)

main = shelly $ do
  csv <- readfile "users.csv"
  mapM_ mk_user (usersFromCSV csv)