I got bitten by a bug (well, I call it bug) in bracketCD from HSH/MissingH demonstrated by the following code bracketCD is very useful for sysadminny one-offs, I use it all the time, but..... I suspect that unless people are very careful, this behavior will affect other users of bracketCD, in potentially very subtle and tricky ways. 1) -- is there a more elegant way to deal with lazy io than the hack below? (putStrLn the last character) 2) -- should MissingH function bracketCD be fixed, and if so how? import System.FilePath.Find (find) import System.Directory (getDirectoryContents, getCurrentDirectory, setCurrentDirectory) import System.Path (bracketCWD) -- from MissingH -- the fixed function, a more restrictive type than bracketCWD which lets you do any io, not just showables myBracketCWD :: Show a => FilePath -> IO a -> IO a myBracketCWD fp action = do oldcwd <- getCurrentDirectory setCurrentDirectory fp a <- action putStrLn $ show . last . show $ a -- force evaluation setCurrentDirectory oldcwd return a -- rather than listing "/", lists dir this module is in tWrong = bracketCWD "/" $ return . take 2 =<< listCurrentWithFind -- this lists filesystem root tRight = myBracketCWD "/" $ return . take 2 =<< listCurrentWithFind listCurrentWithFind = System.FilePath.Find.find (return True) (return True) "." -- for some reason, bracketCWD does the right thing with get tGetContents = myBracketCWD "/" $ return . take 2 =<< getDirectoryContents "." Actual code for bracketCWD in MissingH: -- this is from MissingH, seems there's a bug when attempt to wrap a find command bracketCWD :: FilePath -> IO a -> IO a bracketCWD fp action = do oldcwd <- getCurrentDirectory setCurrentDirectory fp finally action (setCurrentDiurectory oldcwd)