use strict;

my $source = 'VM';
my $COB    = '20080605';

while (<DATA>) {
    if (/^$source.*$COB/) {
        print "Matched $_";
    } ## end if (/^$source.*$COB/)
} ## end while (<DATA>)

__DATA__
VMTKSWPDCN0120080717.TXT
VMTKSWPSLN0120080717.TXT
VMTKSWPDLA0120080717.TXT
CMVMCSHFEN0120080605.TXT
VMTKSWPDLN0120080605.TXT
VMTKSWPTVN0120080605.TXT
VMTKSWPSLN0120080605.TXT
VMTKSWPDLA0120080605.TXT
VMTKSWPTVA0120080605.TXT
VMTKSWPDCN0120080605.TXT
VMTKSWPSLA0120080605.TXT