library question

[Mircea Draghicescu]

I have a couple of questions about the ghc libraries.
What is the easiest way to run an external command from a
Haskell program and capture its output (stdout) as a string in Haskell?
Also, what are the "handles" mentioned in the ghc Posix library
and how do they relate to the file descriptors?
Thanks.

Mircea