安装完的MySQL的默认字符集为 latin1 ，为了要将其字符集改为用户所需要的(比如utf8)，就必须改其相关的配置文件；由于linux下MySQL的默认安装目录分布在不同的文件下；不像windows一样放在同一目录下，只需修改其中的my.ini文件，重起后就生效了；所以先来看看linux下MySQL的数据库文件、配置文件和命令文件分别在不同的目录 ：
1、数据库目录，其所创建的数据库文件都在该目录下
/var/lib/mysql/
2、配置文件 （mysql.server命令及配置文件所在地）
/usr/share/mysql
3、相关命令（如mysql mysqladmin等）
/usr/bin
4、启动脚本（如mysql启动命令）
/etc/rc.d/init.d/
查看默认字符集
#mysql -u root - p
#(输入密码)
mysql> show variables like 'character_set%' ;//或者是status
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | latin1 |
| character_set_connection | latin1 |
| character_set_database | latin1 |
| character_set_filesystem | binary |
| character_set_results | latin1 |
| character_set_server | latin1 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
修改字符集 ：
1.查找/etc目录下是否有my.cnf文件；
#ls -l | grep my.cnf (在/etc下查找是否有my.cnf文件存在)
2.如果没有就要从/usr/share/mysql,拷贝一个到/etc 下，在/usr/share/mysql目录下有五个后缀为.cnf的文件，分别是 my-huge.cnf my-innodb-heavy-4G.cnf my-large.cnf my-medium.cnf my-small.cnf ；从中随便拷贝一个到/etc目录下并将其改为my.cnf文件,我选择的是my-medium.cnf ：
#cp /usr/share/mysql/my-medium.cnf /etc/my.cnf
3.修改my.cnf文件，在该文件中的三个地方加上 default-character-set=utf8（[client] [mysqld] [mysql]）
#vi /etc/my.cnf
修改如下：（红色为添加部分）
[client]
#password = your_password
port = 3306
socket = /var/lib/mysql/mysql.sock
default-character-set=utf8
[mysqld]
port = 3306
socket = /var/lib/mysql/mysql.sock
skip-locking
key_buffer = 16M
max_allowed_packet = 1M
table_cache = 64
sort_buffer_size = 512K
net_buffer_length = 8K
read_buffer_size = 256K
read_rnd_buffer_size = 512K
myisam_sort_buffer_size = 8M
default-character-set=utf8
init_connect='SET NAMES utf8' //此行可不加
[mysql]
no-auto-rehash
default-character-set=utf8
保存退出；
4.重起MySQL服务器，使其设置的内容生效
#/etc/init.d/mysql restart
5. 重新登入mysql；
# mysql -u root - p
#(输入密码)
mysql> show variables like 'character_set%' ;
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |（都生成了utf8，成功了 哈哈哈）
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
mysql启动和停止 操作 ：
可以通过 #/etc/init.d/mysql [start | stop | restart](实现启动，停止，重启)
也可以通过 #service mysql [start | stop | restart](实现启动，停止，重启)
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另外：如果在修改字符集前，尝试在数据库中插入中文，那么当修改了字符集后，在你所插入中文的数据库中（在别的数据库中可能没问题），
通过show variables like 'character_set%'查询的结果可如下：
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | latin1 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
如图，character_set_database仍然会为latin1，我采取的办法是先导出该数据库中数据，如果数据不重要，则可drop此数据库，
然后再重新create一个数据库。
倘若不行的话，可以用命令行的形式
通过MySQL命令行修改:
mysql> set character_set_client=utf8;Query OK, 0 rows affected (0.00 sec)
mysql> set character_set_connection=utf8;
Query OK, 0 rows affected (0.00 sec)
mysql> set character_set_database=utf8;
Query OK, 0 rows affected (0.00 sec)
mysql> set character_set_results=utf8;
Query OK, 0 rows affected (0.00 sec)
mysql> set character_set_server=utf8;
Query OK, 0 rows affected (0.00 sec)
mysql> set character_set_system=utf8;
Query OK, 0 rows affected (0.01 sec)
mysql> set collation_connection=utf8;
Query OK, 0 rows affected (0.01 sec)
mysql> set collation_database=utf8;
Query OK, 0 rows affected (0.01 sec)
mysql> set collation_server=utf8;
Query OK, 0 rows affected (0.01 sec)
查看:
mysql> show variables like 'character_set_%';
+--------------------------+----------------------------+
| Variable_name | Value |
+--------------------------+----------------------------+
| character_set_client | utf8 |
| character_set_connection | utf8 |
| character_set_database | utf8 |
| character_set_filesystem | binary |
| character_set_results | utf8 |
| character_set_server | utf8 |
| character_set_system | utf8 |
| character_sets_dir | /usr/share/mysql/charsets/ |
+--------------------------+----------------------------+
8 rows in set (0.03 sec)
mysql> show variables like 'collation_%';
+----------------------+-----------------+
| Variable_name | Value |
+----------------------+-----------------+
| collation_connection | utf8_general_ci |
| collation_database | utf8_general_ci |
| collation_server | utf8_general_ci |
+----------------------+-----------------+
3 rows in set (0.04 sec)