ありえるのかどうかは置いておいて。もし WordPress に管理者ユーザーが存在しなくなったとして、誰も画面上から管理操作ができなくなった状態を想像してみます。WP-CLI で任意のユーザーに、管理者権限を付与できるのか試してみました。

WP-CLI のインストール

$ curl -O https://raw.githubusercontent.com/wp-cli/builds/gh-pages/phar/wp-cli.phar

$ php wp-cli.phar --info

$ chmod +x wp-cli.phar

$ sudo mv wp-cli.phar /usr/local/bin/wp

$ wp --info

ユーザー一覧と権限グループの操作

$ cd /var/www/html

# root ユーザーで実行したい場合
$ alias wp="wp --allow-root"

$ wp role list
+---------------+---------------+
| name          | role          |
+---------------+---------------+
| Administrator | administrator |
| Editor        | editor        |
| Author        | author        |
| Contributor   | contributor   |
| Subscriber    | subscriber    |
+---------------+---------------+

$ wp user list
+----+------------+--------------+-----------------+---------------------+---------------+
| ID | user_login | display_name | user_email      | user_registered     | roles         |
+----+------------+--------------+-----------------+---------------------+---------------+
| 1  | test       | test         | [email protected] | 2023-09-23 11:25:10 | administrator |
+----+------------+--------------+-----------------+---------------------+---------------+

$ wp user update 1 --role=author
Success: Updated user 1.

$ wp user list
+----+------------+--------------+-----------------+---------------------+--------+
| ID | user_login | display_name | user_email      | user_registered     | roles  |
+----+------------+--------------+-----------------+---------------------+--------+
| 1  | test       | test         | [email protected] | 2023-09-23 11:25:10 | author |
+----+------------+--------------+-----------------+---------------------+--------+

$ wp user update 1 --role=administrator
Success: Updated user 1.

$ wp user list
+----+------------+--------------+-----------------+---------------------+---------------+
| ID | user_login | display_name | user_email      | user_registered     | roles         |
+----+------------+--------------+-----------------+---------------------+---------------+
| 1  | test       | test         | [email protected] | 2023-09-23 11:25:10 | administrator |
+----+------------+--------------+-----------------+---------------------+---------------+

参考

https://developer.wordpress.org/cli/commands/