the UniversalDataWriter always creates the output file (even if not writing the field names), so you will need to delete the file. There's several options to do that:
- use a JavaExecute component in a following phase, and in the Java code you would check the contents of the file (i.e. "it contains just 1 line") and then delete it with standard Java API.
- use a SystemExecute component and execute a script (e.g. a bash script in Unix environment) that performs the same check as above and then deletes it