#!/usr/bin/perl -w 
use strict;
use warnings;
use diagnostics;

my $path="/some/where/over/the/rainbow";

opendir(DIR,$path) or die "$!";
my @list=readdir(DIR);
closedir(DIR);

my @collect=grep /FOO/,@list;
my $count = $#collect + 1;

printf "total count = %d\n",$count;