how do I pull in Tomcat logs, ie catalina.log' periodically

I've read many a post and either I'm just not getting it or it's just not the answer. I want to index the daily catalina log file (per each JVM)say every 5 minutes and of course only want those lines new in the last 5 minute time frame? I'm assuming I need to write a stanze in the inputs.conf but unsure on the format and how to capture the timestamp and save from the last run.

Thanks