process - How to read data from forked processes in Haskell? -

who can give me short example call system command , read out haskell , e.g. print it?

i know can use system.cmd make system commands like: nm, ls, mkdir etc.

but dont need call them need read , make operations readed string

the key library use the process package, provides system.process.

to call command , output:

readprocess       :: filepath   -- command run       -> [string]   -- arguments       -> string         -- standard input       -> io string  -- stdout 

like so:

import system.process  main =     s <- readprocess "/bin/date" [] []     putstrln $ "the date " ++ s 

which runs as:

the date fri apr 29 09:29:29 pdt 2011