How to read out the filesystem usage with a procedure ?

Hi,

first: sorry for my 19 year old school english !

Okay, I'm looking for a solution to read the usage of parts of a Filesystem (mounted part, where the datafiles resides).
going at the machine - df -k - no problem, but I want to read it out with a procedure or something else.

I played a bit with oracle scheduler, and extproc functionality, it's a solution to start a operating system program, but I don't get back a return into my session.

Do someone have an idea ?

Regards

Chris