Q:

Embed a PHP file into INI

I'd like to insert a line, similar to include('path to php file.php'), into php.ini.
Actually I already found this solution from the Internet, however I don't remember which parameter is used in php.ini in this case.
For what: I want to execute a short code (written by php) before every php script from my web server.

A:

If I understand you correctly, you're looking to run a PHP script before all files on your server? If so, the auto-prepend-file directive in php.ini configuration is perfect for this. From the help docs:

Specifies the name of a file that is automatically parsed before the
main file. The file is included as if it was called with the require
function, so include_path is used.
The special value none disables auto-prepending.

Sample Code:
# Inside either main php.ini or child file
auto_prepend_file=/path/to/your/global/php/file.php 

Note that PHP also gives the ability to append a file after every script interpretation as well. There is also a previous SO entry for this with additional information. HTH.

