This can be worked out by calling an EXTERNAL ROUTINE. The required shell script can be stored in a DLL. You register the routine in your PL/SQL routine, and then call it to perform special-purpose processing.
Still, if you find and other alternative then do share it.
Dbms_pipe is another way of doing this. In the pl/sql send a message
and that is captured by the daemon running on the background.
Based on the message sent by the pl/sql , daemon would do the
required job. As daemon runs on the background , it is easy
to execute the host command.
The disadvantage of this is to have a daemon running in the background.
As suggested earliear, for oracle 8i , external procedure is a good