sub dir_ensure {
    for (@_) { # handles multiple DIRs
        my $path = ($_ // die("Dir must be specified")) =~ s!/$!!sr;
        next if -d $path; # DIR is already there
        die("Path '$path' already exists and it's not a DIR") if -e _;
        my $parent = $path =~ m"^(/[^/].*?)/(?!\.{1,2}$)[^/]+$"s
            ? $1 : die("Invalid path '$path'");
        dir_ensure($parent); # ensure parent DIR exists
        mkdir($path) or die("Failed to create DIR $path $!");
    }
}