CentOS下如何完全卸载MySQL？解决卸载不干净的问题
系统：CentOS 6.5，MySQL：MySql 5.6
这里主要解决使用rpm安装的卸载问题，安装方法见：CentOS安装mysql*.rpm提示conflicts with file from package的解决办法
虽然说这里的是使用rpm安装的卸载问题，我觉得使用yum方式安装的如果遇到相同的问题也一样适用。
查看已经安装的服务
rpm –qa|grep -i mysql
-i 作用是不区分大小写
可以看到有两个安装包
MySQL-server-5.6.19-1.linux_glibc2.5.x86_64.rpm
删除这两个服务(去掉后缀)
rpm –e MySQL-client-5.6.19-1.linux_glibc2.5.x86_64
查看残留的目录：
whereis mysql
然后删除mysql目录：
rm –rf /usr/lib64/mysql
删除相关文件：
rm –rf /usr/my.cnf
最关键的：
rm -rf /var/lib/mysql
如果这个目录如果不删除，再重新安装之后，密码还是之前的密码，不会重新初始化！
网上查了很久都没有文章提到这个，最后还是自己摸索找出来的。
卸载完成！怎么确定是不是真的卸载干净了呢？
一是看安装输出：
如果没有卸载干净，安装server时输入只有两行：
| 123 | [root@localhost opt]# rpm -ivh MySQL-server-5.6.19-1.linux_glibc2.5.x86_64.rpm``Preparing... ########################################### [100%]`` 1:MySQL-server ########################################### [100%] |
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卸载干净了安装输入如下：
| 12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182 | [root@localhost opt]# rpm -ivh MySQL-server-5.6.19-1.linux_glibc2.5.x86_64.rpm``Preparing... ########################################### [100%]`` 1:MySQL-server ########################################### [100%]`` 2014-09-23 07:22:43 0 [Warning] ``TIMESTAMP with implicit ``DEFAULT value ``is deprecated. Please use ``--explicit_defaults_for_timestamp server option (see documentation for more details).`` 2014-09-23 07:22:43 26041 [Note] InnoDB: Using atomics ``to ref ``count buffer pool pages`` 2014-09-23 07:22:43 26041 [Note] InnoDB: The InnoDB memory heap ``is disabled`` 2014-09-23 07:22:43 26041 [Note] InnoDB: Mutexes ``and rw_locks use GCC atomic builtins``2014-09-23 07:22:43 26041 [Note] InnoDB: Compressed tables use zlib 1.2.3``2014-09-23 07:22:43 26041 [Note] InnoDB: Using Linux native AIO``2014-09-23 07:22:43 26041 [Note] InnoDB: Using CPU crc32 instructions`` 2014-09-23 07:22:43 26041 [Note] InnoDB: Initializing buffer pool, ``size = 128.0M`` 2014-09-23 07:22:43 26041 [Note] InnoDB: Completed initialization ``of buffer pool`` 2014-09-23 07:22:43 26041 [Note] InnoDB: The ``first specified data file ./ibdata1 did ``not exist: a new ``database to be created!`` 2014-09-23 07:22:43 26041 [Note] InnoDB: Setting file ./ibdata1 ``size to 12 MB`` 2014-09-23 07:22:43 26041 [Note] InnoDB: ``Database physically writes the file ``full : wait...`` 2014-09-23 07:22:43 26041 [Note] InnoDB: Setting log file ./ib_logfile101 ``size to 48 MB`` 2014-09-23 07:22:43 26041 [Note] InnoDB: Setting log file ./ib_logfile1 ``size to 48 MB`` 2014-09-23 07:22:45 26041 [Note] InnoDB: Renaming log file ./ib_logfile101 ``to ./ib_logfile0``2014-09-23 07:22:45 26041 [Warning] InnoDB: New log files created, LSN=45781`` 2014-09-23 07:22:45 26041 [Note] InnoDB: Doublewrite buffer ``not found: creating new``2014-09-23 07:22:45 26041 [Note] InnoDB: Doublewrite buffer created`` 2014-09-23 07:22:45 26041 [Note] InnoDB: 128 ``rollback segment(s) are active.`` 2014-09-23 07:22:45 26041 [Warning] InnoDB: Creating ``foreign key constraint system tables.`` 2014-09-23 07:22:45 26041 [Note] InnoDB: ``Foreign key constraint system tables created`` 2014-09-23 07:22:45 26041 [Note] InnoDB: Creating tablespace ``and datafile system tables.`` 2014-09-23 07:22:45 26041 [Note] InnoDB: Tablespace ``and datafile system tables created.`` 2014-09-23 07:22:45 26041 [Note] InnoDB: Waiting ``for purge ``to start`` 2014-09-23 07:22:45 26041 [Note] InnoDB: 5.6.19 started; log ``sequence number 0`` A random root ``password has been ``set . You will find it ``in '/root/.mysql_secret' .`` 2014-09-23 07:22:46 26041 [Note] Binlog ``end``2014-09-23 07:22:46 26041 [Note] InnoDB: FTS optimize thread exiting.``2014-09-23 07:22:46 26041 [Note] InnoDB: Starting shutdown...`` 2014-09-23 07:22:48 26041 [Note] InnoDB: Shutdown completed; log ``sequence number 1625977 2014-09-23 07:22:48 0 [Warning] ``TIMESTAMP with implicit ``DEFAULT value ``is deprecated. Please use ``--explicit_defaults_for_timestamp server option (see documentation for more details).`` 2014-09-23 07:22:48 26065 [Note] InnoDB: Using atomics ``to ref ``count buffer pool pages`` 2014-09-23 07:22:48 26065 [Note] InnoDB: The InnoDB memory heap ``is disabled`` 2014-09-23 07:22:48 26065 [Note] InnoDB: Mutexes ``and rw_locks use GCC atomic builtins``2014-09-23 07:22:48 26065 [Note] InnoDB: Compressed tables use zlib 1.2.3``2014-09-23 07:22:48 26065 [Note] InnoDB: Using Linux native AIO``2014-09-23 07:22:48 26065 [Note] InnoDB: Using CPU crc32 instructions`` 2014-09-23 07:22:48 26065 [Note] InnoDB: Initializing buffer pool, ``size = 128.0M`` 2014-09-23 07:22:48 26065 [Note] InnoDB: Completed initialization ``of buffer pool`` 2014-09-23 07:22:48 26065 [Note] InnoDB: Highest supported file format ``is Barracuda.`` 2014-09-23 07:22:48 26065 [Note] InnoDB: 128 ``rollback segment(s) are active.`` 2014-09-23 07:22:48 26065 [Note] InnoDB: Waiting ``for purge ``to start`` 2014-09-23 07:22:48 26065 [Note] InnoDB: 5.6.19 started; log ``sequence number 1625977`` 2014-09-23 07:22:48 26065 [Note] Binlog ``end``2014-09-23 07:22:48 26065 [Note] InnoDB: FTS optimize thread exiting.``2014-09-23 07:22:48 26065 [Note] InnoDB: Starting shutdown...`` 2014-09-23 07:22:50 26065 [Note] InnoDB: Shutdown completed; log ``sequence number 1625987 A RANDOM ``PASSWORD HAS BEEN ``SET FOR THE MySQL root ``USER !`` You will find that ``password in '/root/.mysql_secret' . You must change that ``password on your ``first connect ,``no other statement but ``'SET PASSWORD' will be accepted.`` See the manual ``for the semantics ``of the ``'password expired' flag. Also, the account ``for the anonymous ``user has been removed. In addition, you can run: /usr/bin/mysql_secure_installation which will also give you the ``option of removing the test ``database .`` This ``is strongly recommended ``for production servers. See the manual ``for more instructions. Please report ``any problems ``at http://bugs.mysql.com/ The latest information about MySQL ``is available ``on the web ``at http://www.mysql.com Support MySQL ``by buying support/licenses ``at http://shop.mysql.com New ``default config file was created ``as /usr/my.cnf ``and`` will be used ``by default by the server ``when you start it.`` You may edit this file ``to change server settings |
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最后一段中提示了重要信息，很多人因为不喜欢读英文，导致接下来不知道怎么操作！
二就是安装完成，启动服务之后
使用命令：“mysql -uroot -p”输入你之前安装后设置的密码，看能不能登录，如果还可以登录，说明没有卸载干净！
