mysql默认安装上没有my.cnf文件的 需要我们手动去创建

第一步：使用mysql --verbose --help | grep my.cnf查看MySQL默认指定的my.cnf路径。

第二步：直接在终端中输入sudo vim /etc/my.cnf在etc文件夹下创建my.cnf文件，然后将配置写入，就可以了。

# Example MySQL config file for medium systems.  
                              #  
                              # This is for a system with little memory (32M - 64M) where MySQL plays  
                              # an important part, or systems up to 128M where MySQL is used together with  
                              # other programs (such as a web server)  
                              #  
                              # MySQL programs look for option files in a set of  
                              # locations which depend on the deployment platform.  
                              # You can copy this option file to one of those  
                              # locations. For information about these locations, see:  
                              # http://dev.mysql.com/doc/mysql/en/option-files.html  
                              #  
                              # In this file, you can use all long options that a program supports.  
                              # If you want to know which options a program supports, run the program  
                              # with the "--help" option.  
                              # The following options will be passed to all MySQL clients  
                              [client]
                              default-character-set=utf8
                              #password   = your_password  
                              port        = 3306  
                              socket      = /tmp/mysql.sock   
                              # Here follows entries for some specific programs  
                              # The MySQL server  
                              [mysqld]
                              #skip-grant-tables
                              character-set-server=utf8
                              init_connect='SET NAMES utf8
                              port        = 3306  
                              socket      = /tmp/mysql.sock  
                              skip-external-locking  
                              key_buffer_size = 16M  
                              max_allowed_packet = 1M  
                              table_open_cache = 64  
                              sort_buffer_size = 512K  
                              net_buffer_length = 8K  
                              read_buffer_size = 256K  
                              read_rnd_buffer_size = 512K  
                              myisam_sort_buffer_size = 8M  
                              character-set-server=utf8  
                              init_connect='SET NAMES utf8' 
                            # Don't listen on a TCP/IP port at all. This can be a security enhancement,  
                            # if all processes that need to connect to mysqld run on the same host.  
                            # All interaction with mysqld must be made via Unix sockets or named pipes.  
                            # Note that using this option without enabling named pipes on Windows  
                            # (via the "enable-named-pipe" option) will render mysqld useless!  
                            #   
                            #skip-networking  
                             
                             # Replication Master Server (default)  
                             # binary logging is required for replication  
                              log-bin=mysql-bin  
                             
                             # binary logging format - mixed recommended  
                                binlog_format=mixed  
                             
                             # required unique id between 1 and 2^32 - 1  
                                  # defaults to 1 if master-host is not set  
                                  # but will not function as a master if omitted  
                                  server-id   = 1  
                             
                                # Replication Slave (comment out master section to use this)  
                                #  
                                # To configure this host as a replication slave, you can choose between  
                                # two methods :  
                                #  
                                # 1) Use the CHANGE MASTER TO command (fully described in our manual) -  
                                #    the syntax is:  
                                #  
                                #    CHANGE MASTER TO MASTER_HOST=<host>, MASTER_PORT=<port>,  
                                #    MASTER_USER=<user>, MASTER_PASSWORD=<password> ;  
                                #  
                                #    where you replace <host>, <user>, <password> by quoted strings and  
                                #    <port> by the master's port number (3306 by default).  
                                #  
                                #    Example:  
                                #  
                                #    CHANGE MASTER TO MASTER_HOST='125.564.12.1', MASTER_PORT=3306,  
                                #    MASTER_USER='joe', MASTER_PASSWORD='secret';  
                                #  
                                # OR  
                                #  
                                # 2) Set the variables below. However, in case you choose this method, then  
                                #    start replication for the first time (even unsuccessfully, for example  
                                #    if you mistyped the password in master-password and the slave fails to  
                                #    connect), the slave will create a master.info file, and any later  
                                #    change in this file to the variables' values below will be ignored and  
                                #    overridden by the content of the master.info file, unless you shutdown  
                                #    the slave server, delete master.info and restart the slaver server.  
                                #    For that reason, you may want to leave the lines below untouched  
                                #    (commented) and instead use CHANGE MASTER TO (see above)  
                                #  
                                # required unique id between 2 and 2^32 - 1  
                                # (and different from the master)  
                                # defaults to 2 if master-host is set  
                                # but will not function as a slave if omitted  
                                #server-id       = 2  
                                #  
                                # The replication master for this slave - required  
                                #master-host     =   <hostname>  
                                #  
                                # The username the slave will use for authentication when connecting  
                                # to the master - required  
                                #master-user     =   <username>  
                                #  
                                # The password the slave will authenticate with when connecting to  
                                # the master - required  
                                #master-password =   <password>  
                                #  
                                # The port the master is listening on.  
                                # optional - defaults to 3306  
                                #master-port     =  <port>  
                                #  
                                # binary logging - not required for slaves, but recommended  
                                #log-bin=mysql-bin  
                             
                                  # Uncomment the following if you are using InnoDB tables  
                                  #innodb_data_home_dir = /usr/local/mysql/data  
                                  #innodb_data_file_path = ibdata1:10M:autoextend  
                                  #innodb_log_group_home_dir = /usr/local/mysql/data  
                                  # You can set .._buffer_pool_size up to 50 - 80 %  
                                  # of RAM but beware of setting memory usage too high  
                                  #innodb_buffer_pool_size = 16M  
                                  #innodb_additional_mem_pool_size = 2M  
                                  # Set .._log_file_size to 25 % of buffer pool size  
                                  #innodb_log_file_size = 5M  
                                  #innodb_log_buffer_size = 8M  
                                  #innodb_flush_log_at_trx_commit = 1  
                                  #innodb_lock_wait_timeout = 50  
                             
                                    [mysqldump]  
                                    quick  
                                    max_allowed_packet = 16M  
                             
                                      [mysql]  
                                      no-auto-rehash  
                                      # Remove the next comment character if you are not familiar with SQL  
                                      #safe-updates  
                                      default-character-set=utf8   
                             
                                    [myisamchk]  
                                    key_buffer_size = 20M  
                                    sort_buffer_size = 20M  
                                    read_buffer = 2M  
                                    write_buffer = 2M  
                             
                                      [mysqlhotcopy]  
                                      interactive-timeout
                            

第三步：设置读写权限sudo chmod 664 /etc/my.cnf