#! perl
use strict;
use warnings;

for (
       'ASQWERFD.YYxxxx.W12345.XYZQW.D072413.csv',
       'ASQWERFD.YYxxxx.W12345.XYZQW.D072413.txt',
       'ASQWERFD.YYxxxx.W12345.XYZQW.D072413.dat',
       'ASQWERFD.YYxxxx.W12345.KMHYT.D072413.csv',
       'ASQWERFD.YYxxxx.W12345.XYZQA.D072413.csv',
    )
{
    if (/ .{10,} (?: XYZQW | KMHYT) .* \. (?: csv | txt) $ /ix)
    {
        print "Matched  $_\n";
    }
    else
    {
        print "Ignoring $_\n";
    }
}