There are possible a few solutions to do this but are not recommended. A possible solution is to execute a batch file with a java procedure EXECOSCMD or EXECUTEOSCMD . First you need to configure the utl_file_dir database parameter to the appropriate directory and then use executeoscmd to run the batch file or script on your server.
We strongly recommend against this practice and recommend that you find a work around through an interface table based on which an external program runs in a cron etc.
Another solution is available as a script at http://orafaq.com/scripts/plsql/oscmd.txt


