So does that mean functionality has been lost in the move from ghc-6.0.1?

No, the behaviour is improved in 6.2 because we're now careful to escape quotes before passing the command-line to the operating system. I think confusion has arisen because Simon pointed out that there's no way, on Windows, to pass this sequence of characters as an argument to a command: \" This is not entirely true, I just discovered that the sequence \\\" will turn into \". But in general, the sequence \\ does not turn into \. Windows' command-line quoting rules are highly mysterious, to say the least. So the patch I posted is not complete. It looks like rawSystem should additionally translate \" as \\\".

Because that (on win98) happily accepts such useful contraptions as

System.Cmd.rawSystem "\"c:\\silly space\\Vim\\vim62\\gvim.exe\" --servername GVIM --remote-send \":echo \\\"hi \\\\\\\" there\\\"<cr>\"" >>= print

The idea is that you should pass to rawSystem *exactly* the command and arguments you want to run, with no quoting except that required by the Haskell lexical syntax. You'll notice that rawSystem now takes the command and list of arguments separately in 6.2. The implementation of rawSystem will attempt to compensate for the internal translation that Windows does on the command-line; on Unix no translation is necessary. So clients of rawSystem should be more portable, because they don't have to know about quoting that happens under the hood. Your example will probably work once it's reformulated for 6.2's version of rawSystem, and once we fix rawSystem in light of the \\\" hack I discovered above. Cheers, Simon