Alternately to what JavaFan said, you could also do this:

use File::Slurp;

chdir "/tmp/test";

my @files = grep { -f and /^\d{8}\.\d{6}\.host\d\.\d{1,6}$/ } read_dir
+ ".";
print "Got ". scalar(@files) . "\n";
[download]

Of course, if the script is going to do anything else, and needs to keep track of the original working directory, use Cwd to find out where you are before you do chdir.