How do I get Workflow type from external command

System

I have a perl script that is triggered as an external command from a workflow. I would like the script to do different things depending on if the workflow is triggered by a submit or a tt_deletedcr. How do I find out from within my script ? There seem to be no appropriate values in the task or workflow objects. Failing a solution to this I realize that I can create completely separate workflows and commands for each of the submit and delete scenarios but this seems like overkill.
Your help much appreciated ...