Moodle requires the iconv PHP extension.

Moodle requires the iconv PHP extension. Please install or enable the iconv extension.
Moodle的安装版本为moodle-latest-36.tgz
ubuntu版本为
moodle@moodle:/$ cat /proc/version
Linux version 4.18.0-15-generic (buildd@lgw01-amd64-007) (gcc version 8.2.0 (Ubuntu 8.2.0-7ubuntu1)) #16-UbuntuSMP Thu Feb 7 10:56:39 UTC 2019
php的版本为
moodle@moodle:/$ php -v
PHP 7.2.15-0ubuntu0.18.10.1 (cli) (built: Feb 8 2019 14:54:22) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
with Zend OPcache v7.2.15-0ubuntu0.18.10.1, Copyright (c) 1999-2018, by Zend Technologies
我在php.ini里面看了确实没有iconv这个扩展插件
没有办法，只好进行apt安装
安装的时候却提示
moodle@moodle:/$ sudo apt-get install php7.2-iconv
Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'php7.2-common' instead of 'php7.2-iconv'
php7.2-common is already the newest version (7.2.15-0ubuntu0.18.10.1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
moodle@moodle:/$ sudo apt-get install php7.2-common
Reading package lists... Done
Building dependency tree
Reading state information... Done
php7.2-common is already the newest version (7.2.15-0ubuntu0.18.10.1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
moodle@moodle:/$
请问我该如何安装iconv这个扩展插件并启用他