calling a seperate program and supplying command line args.

How to basically? I've not had much luck finding much in the way of doc's in ghc on how to do this?...basically I have a compiler in haskell and I want to call a parser which is written in Java. The parser is a .NET binary, it spits out a text file containing the parse tree which I then suck up and do the usual compiler things with. I need to supply the java parser command line args i.e the file to parse etc.. Thanks heaps Jason.