Note the hk script gives you a richer default environment, including System.Environment and a bunch of other commonly used modules.

Also, some magic to sort of detect what you want, in the case of whether you give it a pure function vs an IO etc. For one offs on the command line, a slightly less picky type check seems to make sense in my opinion. In the case that it doesn't work, it lets you edit the script in a text editor, there by showing you what the real haskell looks like.

Not that I am especially proud, the implementation could be cleaned up a lot I am sure, but the user interface is failry nice I think.

One caveat I probably should mention in the README but didn't, is that your script is copied to a file stored under /tmp, so you don't want to put passwords or anything of that matter in it.