Why you need to Restart SSH Service
Sometimes you may need to change some configurations inside MySQL configuration file my.cnf , so after you made or modify the MySQL cnf file ,properly you need to Stop and Start or Restart MySQL Service.
How To Restart MySQL Service under Linux / UNIX
The following examples using the restart command in case you want to stop the service you can use stop command and use start command to start stopped service.
You have run these command under root/administrator privileges .
Restart MySQL Service On CentOS/RHEL/Fedora/Scientific Linux version 4.x/5.x/6.x
service mysqld restart
Or
/etc/init.d/mysqld restart
Restart MySQL on CentOS/RHEL/Fedora/Scientific Linux version 7.x
systemctl restart mysqld
Restart MySQL on Debian/Ubuntu Linux
/etc/init.d/mysql restart
Or
service mysql restart
Restart MySQL On FreeBSD Unix
/usr/local/etc/rc.d/mysql-server start