To restart, start or stop MySQL server from the command line, type the following at the shell prompt…
On Linux start/stop/restart from the command line:
| /etc/init.d/mysqld start | 
| /etc/init.d/mysqld stop | 
| /etc/init.d/mysqld restart | 
Some Linux flavours offer the service command too
| service mysqld start | 
| service mysqld stop | 
| service mysqld restart | 
or
| service mysql start | 
| service mysql stop | 
| service mysql restart | 
On OS X to start/stop/restart MySQL from the command line:
| sudo/usr/local/mysql/support-files/mysql.server start | 
| sudo/usr/local/mysql/support-files/mysql.server stop | 
| sudo/usr/local/mysql/support-files/mysql.server restart |