[Haskell-cafe] Checking for correct invocation of a command line / shell haskell program

New wiki page: Checking for correct invocation of a command line haskell program at http://haskell.org/haskellwiki/Checking_for_correct_invocation_of_a_command_... This is a simple cookbook / boilerplate example I thought should go in a haskell wiki somewhere. I linked it from http://haskell.org/haskellwiki/Simple_unix_tools Perhaps it could be linked from other places as well. Hope this helps!