Linux

To stop, start, or restart MySQL server under Linux, type:
# /etc/rc.d/init.d/mysqld stop
# /etc/rc.d/init.d/mysqld start
# /etc/rc.d/init.d/mysqld restart

FreeBSD

To stop or start MySQL server under FreeBSD, type:
# /usr/local/etc/rc.d/mysqld_server.sh stop
# /usr/local/etc/rc.d/mysql_server.sh start

To restart MySQL server under FreeBSD, run:
# /usr/local/etc/rc.d/mysql_server.sh stop
# sleep 10
# /usr/local/etc/rc.d/mysql_server.sh start