Turn on php debugging mode under Ubuntu and display error message

　The default setting of PHP under Ubuntu is not to display error messages. If the program makes an error, it will display an "error message that cannot process this request", which is very inconvenient in a development environment.

In fact, we only need to edit the apache configuration file

　1. My apache configuration file directory is /etc/apache2/apache2.conf

　sudo vim /etc/apache2/apache2.conf

　Add the following two lines at the end

php_flag display_errors on
php_value error_reporting 2039

　2. Restart apache

　sudo service apache2 restart

　This completes the display of the error message.

Note: If it still doesn’t work, change the configuration under php.ini (I haven’t changed it, but it can be displayed, because the code added above is already enabled)

　sudo vim /etc/php/7.0/cli/php.ini

Search for display_errors. The default is display_errors=Off. Change it to display_errors=On. Save and exit and restart apache2.