use Data::Dumper;
my %date_hash = (
		"Jan" => "01",
		"Feb" => "02",
		"Mar" => "03",
		"Apr" => "04",
		"May" => "05",
		"Jun" => "06",
		"Aug" => "07",
		"Sep" => "08",
		"Oct" => "10",
		"Nov" => "11",
		"Dec" => "12"
	);
my $file=".\\tmp.txt";
my $out=".\\out.txt";
open FILE, $file || die "Can't open file: $!";
open OUT, ">$out" || die "Can't open file: $!";
while(<FILE>){
	(m/(.+.WARNING)(.+)/g) 
	while ( (my $key, my $value) = each(%date_hash)) {
		if (s/$key/$value/g) {
		}
	}
}
}
close FILE;

print Dumper($2);
close OUT;