list snippets without category terms

wp eval '
$args = [
    "post_type"      => "snippet",
    "posts_per_page" => -1,
    "tax_query"      => [
        [
            "taxonomy" => "snippet_category",
            "operator" => "NOT EXISTS",
        ],
    ],
];
$posts = get_posts($args);
if (empty($posts)) {
    echo "No snippet posts without a category found.\n";
} else {
    $ids = wp_list_pluck($posts, "ID");
    echo implode(" ", $ids) . "\n";
}'