PL/SQL :: Executing A Shell Script From A Trigger

I have to write a script to do the following requirement. There is a file called BUSINESS_DATE.TXT. This file get updated once the oracle partition created. In Oracle, artition will be created every day. There is a seperate script scheduled to take care ORACLE partition creation. The above file will have only one row. i.e. 03092012

If Oracle partition creation job failed, the above file won't be updated. My requirement is, I have to check whether the BUSINESS_DATE file is updated today or not. If yes, I will have to move the files from common area to input file directory to process those files. All file name will amend with current date. i.e .

LIDDIFD03092012.TXT

The key part is to check the BUSINESS_DATE.TXT file is updated properly or not. We don't know what time the file will get updated. So we are planning to schedule the new script to run for every 15 mins to check whether the file is updated or not

But...I just thought instead of writing a shell script to do the above one, Why shouldn't I capture the date in a table (New table needs to be created) and use ORACLE TRIGGER to run the shell script to move the files from common area to input file directory to process those files?

My Proposal in ORACLE :

Create table business_date
(
rep_date varchar(15),
curr_timestamp timestamp
)

Once the oracle partition created , one row will be inserted into the above table. This adjustment needs to be implemented partition script. Once this table get record, TRIGGER should call SHELL SCRIPT to move the files from common area to input area.

If I implement ORACLE TRIGGER, The script which will check whether the file got updated or not for 15 mins is not required.