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

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

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

my $count = 0;

foreach my $file(@file_list){
    open(FIN,"< $file") or die "$file: $!";
    my @slurp=<FIN>;
    close(FIN);

    my @collect=grep /FOO/,@slurp;
    $count += ($#collect + 1);
}

printf "My total count was: %d\n",$count;