Question: As I work my way through Learn You as Haskell, I have been writing small File IO programs. Unlike the example in that book, where the author reads from one file, writes altered data to a temp file and then deletes the original file and renames the temp file, I have been trying to read from a given file, alter the data and then overwrite the same file with the new data. Is this possible? In a main do block I have tried: contents <- readFile fileName -- do stuff to contents-- writeFile fileName result After using appendFile to add items to the file, when I call the function to read and write I get this error: openFile: resource busy, (file is locked) I have also tried using the file handles like so: handle <- openFile fileName ReadWriteMode contents <- hGetContents handle -- do stuff to contents -- hPutStr handle results hClose handle I have also tried opening with one handle to read, closing it, then using another handle for writing, but the error message is that the handle to the file is closed. I am thinking that the the author of LYAH maybe has good reasons to use a temp file, or is there another way that is not too difficult to grasp?? Many thanks, Geoffrey