php7.3。你可以尝试安装这些模块。这对我很管用。

sudo apt-get install libapache2-mod-php7.3

sudo service apache2 restart

此问题的另一个可能原因可能是您试图在UserDir模块的“用户目录”中运行脚本。在用户目录下运行PHP脚本默认是禁用的。如果脚本位于主文件夹的public_html目录中，并且您试图从http://localhost/~your_username访问它，那么就会遇到这个问题。

要解决这个问题，打开/etc/apache2/mods-enabled/php7.2.conf。必须注释或删除底部的标记块

<IfModule mod_userdir.c>
    <Directory /home/*/public_html>
        php_admin_flag engine Off
    </Directory>
</IfModule>

这种情况又发生在我身上，服务器下载html文件，而不是处理。我已经有一段时间没有在电脑上使用web服务器apache了，同时Ubuntu从最初安装的LTS更新了两个版本。现在是这样

$ cat /etc/issue
Ubuntu 16.04 LTS

php是这样工作的:

$ sudo apt-get install lamp-server^
$ sudo a2enmod php7.0
$ sudo service apache2 restart 

web服务器现在正在解析php。也许现在要更新一些网页，因为php7.0现在运行在php5之前的地方。哦。

听起来你的配置好像有问题，下面是一些你可以检查的东西:

Make sure that PHP is installed and running correctly. This may sound silly, but you never know. An easy way to check is to run php -v from a command line and see if returns version information or any errors. Make sure that the PHP module is listed and uncommented inside of your Apache's httpd.conf This should be something like LoadModule php5_module "c:/php/php5apache2_2.dll" in the file. Search for LoadModule php, and make sure that there is no comment (;) in front of it. Make sure that Apache's httpd.conf file has the PHP MIME type in it. This should be something like AddType application/x-httpd-php .php. This tells Apache to run .php files as PHP. Search for AddType, and then make sure there is an entry for PHP, and that it is uncommented. Make sure your file has the .php extension on it, or whichever extension specified in the MIME definition in point #3, otherwise it will not be executed as PHP. Make sure you are not using short tags in the PHP file (<?), these are not enabled on all servers by default and their use is discouraged. Use <?php instead (or enable short tags in your php.ini with short_open_tag=On if you have code that relies on them). Make sure you are accessing your file over your webserver using an URL like http://localhost/file.php not via local file access file://localhost/www/file.php

最后，查看PHP手册以获得更多的设置技巧。

我知道这听起来很傻……但这种情况很少发生。

检查您是否试图从

**http://localhost/info.php**

而不是来自

file:///var/www/info.php

Ps >你可以注意到如果你从shell写

php info.php 

它回答的代码(它意味着PHP函数)..

我发现了另一个导致这个问题的问题，并且已经解决了它。我不小心将脚本保存为UTF-16编码。PHP5似乎不能识别<?PHP标签默认为16位编码。