unix script from sql

SELECT apps.host_command(‘ls -ltr’) FROM dual;
--
SELECT apps.host_command(‘chmod 777 /devel/appl/xxcus/1.0.0/bin/filename’) FROM dual;
--
CREATE OR REPLACE FUNCTION host_command( cmd IN VARCHAR2 )
RETURN INTEGER
IS
STATUS NUMBER;
errormsg VARCHAR2(80);
pipe_name VARCHAR2(30);
BEGIN
pipe_name := ‘HOST_PIPE’;
dbms_pipe.pack_message( cmd );
STATUS := dbms_pipe.send_message(pipe_name);
RETURN STATUS;
END;