How can I know which 'php.ini' file is used?

I search the path where the php.ini file is located in our Linux Ubuntu server, and I found many php.ini files when executing the command find / -name php.ini. So how can I know exactly from a PHP script web page where the php.ini is located?

You can use php_ini_loaded_file().

Taken from php.net:

$inipath = php_ini_loaded_file();
if ($inipath) {
    echo 'Loaded php.ini: ' . $inipath;
} else {
    echo 'A php.ini file is not loaded';
}

You may also want to check php_ini_scanned_files().

Also, you should note that if you run a PHP script from CLI, it's possible that a different php.ini file will be used than if a server (e.g., nginx or Apache) runs it.

Other options:

• php -i|grep 'php.ini'
• create info.php that contains <?php phpinfo(); in the webroot, and run it in your browser