[ixp1200] file operations in .ind scripts?

Hello, I am using IXP1200 simulator, and want to run an existing IXP1200 application with my routing table inputs. Currently, the applications routing table is set in .ind scripts using route_add function. The routing table I want to use instead is in a text file, and I will like a .ind script that reads the file and sets the application's route table accordingly. I don't see any clear support for that in the .ind scripts. Can anyone suggest how to do this? Thanks, Arvind