您的默认PHP 8.0：

php -v

运行已安装的PHP 8.1：

/usr/bin/php8.1 -v

您可以通过以下方式切换活动版本：

sudo update-alternatives --config php

输出

There are 2 choices for the alternative php (providing /usr/bin/php).

  Selection    Path             Priority   Status
------------------------------------------------------------
  0            /usr/bin/php8.0   80        auto mode
  1            /usr/bin/php8.1   70        manual mode
* 2            /usr/bin/php8.0   80        manual mode

Press <enter> to keep the current choice[*], or type selection number: 1
update-alternatives: using /usr/bin/php8.1 to provide /usr/bin/php (php) in manual mode