Common Options of the MySQL Server (mysqld) and the MySQL Client Tools(mysql, mysqladmin, mysqldump, mysqlimport, etc.)
--help Displays a brief operation introduction. --print-defaults Displays default values for options; default values can come from configuration files or system variables. --nodefaults Causes no configuration files to be read at startup. --defaults-file=filename Causes only this configuration file to be read at startup. --defaults-extra-file=filename First the global configuration file is read, and then filename, and finally (only under Unix/Linux), the user-specific configuration file. --port=n Specifies the TCP/IP port over which communication takes place (usually 3306). --socket=filename Specifies which socket file should be used for local communication between client and server (only under Unix/Linux; by default usually /var/lib/mysql/mysql.sock). If named pipes are used under Windows, then socket specifies the name of the named pipe (by default MySQL). --version Displays the version number of the program.