SFTP adapter File Name pattern

Hi Team,

Please help in forming regular expression for Filename in SFTP adapter.

I tried with [a-zA-Z0-9_], [a-zA-Z0-9_].*, [a-zA-Z0-9_].txt ...etc, which didn't worked.

The following are the different type of files available in same directory

CPT_PO_TEXT_%02-06-09%_%15-28-50%.txt

P20120927060000.xls

APZ_20120927_T05D.csv

AIMS_POL_151209_1741.TXT

The numeric values change day by day and have configured 4 sender comm channels.

Please let me know what pattern can be used to pick above mentioned files along with its extensions.