module System (
ExitCode(ExitSuccess,ExitFailure),
getArgs, getProgName, getEnv, system, exitWith ) where
data ExitCode = ExitSuccess | ExitFailure Int
deriving (Eq, Ord, Read, Show)
getArgs :: IO [String] getProgName :: IO String getEnv :: String -> IO String system :: String -> IO ExitCode exitWith :: ExitCode -> IO a |
These functions interact with the system running the Haskell program. These allow the program to accept command line arguments (getArgs), read the name under which the program was invoked (getProgName), read environment variables (getEnv), exit returning status (exitWith), and execute shell or other operating system commands (system). Some operating systems may not support all of these functions.