Run Unix command using PL/SQL Is it possible to run a Unix command using a query in Oracle?

I want to run simple commands (like df -h) using a query.

Is this at all possible or am I wasting my time? I don't want to use a different language like Java or C to call a procedure, it needs to purely PL/SQL.
You can use the DBMS_Scheduler 

DBMS_SCHEDULER.create_program
(
program_name =&gt; 'testScript',
program_type =&gt; 'EXECUTABLE',
program_action =&gt; '/home/someone/scripts/script.sh',
number_of_arguments =&gt; 0,
enabled =&gt; TRUE,
comments =&gt; 'Just a Test'
);
end;
/


and a little hosekeeping:

exec DBMS_SCHEDULER.drop_program(PROGRAM_NAME =&gt; 'testScript');