use strict;
use warnings;

############  SCAN DIRECTORY SUBROUTRINE ####################
{
    my $paths = [];

    sub dir_listing {
        my ($root) = @_;
        $root .= '/' unless $root =~ /\/$/;
        for my $f (glob "$root*") {
            push @{$paths}, $f if $f =~ m/\.rar$/;
            dir_listing($f) if -d $f;
        }
        return $paths;
    }
}

my $rar_files = dir_listing('/a/path');

if (scalar @{$rar_files}) {
    ###do something;
    print "paths defined";
}
else {
    #do something else;
    print "paths not defined";
}