I have a big file that looks like this:
7f0c41d6-f9c6-47aa-a034-d40bc629c973.csv 159890 159891 24faaed6-62ee-4175-8430-5d73b09911c8.csv 159907 5bad221f-25ef-44fa
([0-9a-zA-Z-]*.csv$)
This is the regex code that only select the filename ending with .csv extensions.
Hope this will help you.