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import System.Environment (getEnv)
import System.IO.Error (catchIOError, isDoesNotExistError)
main :: IO ()
main = do
term <- getEnv "PATH"
putStrLn "Got $PATH"
fish <- getEnv "One fish, two fish, red fish, blue fish" `catchIOError` getEnv_except
putStrLn fish
getEnv_except :: IOError -> IO String
getEnv_except ioe
| isDoesNotExistError ioe = return ""
| otherwise = ioError ioe
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