opendir DIR, $logs or die "Cannot open dir $logs: $!\n";
my @files = grep /^access_log\.\d+\.gz$/, readdir DIR;
close DIR;

open TAR, "|tar -czpf $target_file - >savetarout"
    or die "Cannot open tar: $!\n";
print TAR $_, "\n" for @files;
close TAR or die "error closing TAR: $!\n";