1. 用mysql端口和服务查询是否启动

   port=`netstat -tlunp | grep mysql | wc - l`

   process=`ps -ef | grep mysql|wc - l`

    

   if [$port -ne  1 ] && [ $process -ne 2 ]

    then

        echo "mysql is running"

    else

        echo "mysql is stop" 

        /etc/init.d/mysqld start

    fi

2.通过查询版本号来确认是否开启mysql

    mysql -uroot -pyzg1314520 -e "select version()"  &> /dev/null

    if [$? -ne 0 ]

      then

         /etc/init.d/mysqld start

    else

        echo "mysqld is running"

    fi

如果mysqld是关闭状态的话，查询版本号

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

就会提示mysql是关闭的。