If you want access to its I/O streams as well, you can use Posix.popen, which is not standard Haskell 98, I think, but it's in GHC.

Even worse, it is not portable (AFAICT)! I'm worried by the tendency towards Posix, at a time when, e.g., GHC by default no longer supports this on Windows (went missing in the move from cygwin to mingw). Some also thought Posix overkill, and wanted a portable replacement for the most-commonly-wanted functionality subset.. Could someone in the know please summarise the state of Posix-support in Haskell implementations in general? I've cc-ed to the libraries list - perhaps someone there could comment on the state of portable replacements for Posix functionality, especially for popen and friends? I seem to recall a very promising discussion about portable and flexible ways to start subprocesses a while ago - has that led to any concrete libraries? Cheers, Claus