MySQL database server (my.conf), PHP programming language (php.ini) and Apache HTTP server (http.conf), which together with Linux form the LAMP (Linux Apache Mysql/MariaDB PHP) stack.
A configuration file (or config file) contains system-related or application settings. It gives developers and administrators control over the operation of the system or an application.
In Linux Directory Structure, the /etc directory or its sub-directories store system related or application configuration files.
How To Find MySQL (my.conf) Configuration File
You can locate the MySQL configuration file using the mysql command-line tool or mysqladmin, a client for managing a MySQL server.
The following commands will display the mysql or mysqladmin help page, which includes a section that talks about the files (configuration files) from which default options are read.
In the commands below, the grep option -A displays NUM lines of trailing context after matching lines.
$ mysql --help | grep -A1 'Default options' OR $ mysqladmin --help | grep -A1 'Default options'
How To Find PHP (php.ini) Configuration File
PHP can be controlled from the terminal using php command-line utility, in conjunction with the -i switch which enables showing of PHP information and configurations and grep command help you to can find the PHP configuration file like so:
$ php -i | grep "Loaded Configuration File"
Find Apache http.conf/apache2.conf Configuration File
You can invoke apache2 directly (which is not recommended in most cases) or administer it using apache2ctl control interface as below with the -V flag which shows the version and builds parameters of apache2:
--------- On CentOS/RHEL/Fedora --------- $ apachectl -V | grep SERVER_CONFIG_FILE --------- On Debian/Ubuntu/Linux Mint --------- $ apache2ctl -V | grep SERVER_CONFIG_FILE