1. 验证 mysql 是否安装
2. 卸载之前的 mysql
3. 安装新的 mysql
4. 配置 root 用户密码
5. 总结 Linux 重新安装 Mysql 的步骤

1. 验证 mysql 是否安装

rpm -qa | grep -i mysql
# -i：不区分大小写

• 验证 mysql 是否安装：

[root@localhost ~]# rpm -qa | grep -i mysql
mysql-server-5.1.73-5.el6_6.i686
mysql-libs-5.1.73-5.el6_6.i686
mysql-5.1.73-5.el6_6.i686
perl-DBD-MySQL-4.013-3.el6.i686

2. 卸载之前的 mysql

rpm -e --nodeps xx
# -e：卸载
# --nodeps：强制性

• 卸载 mysql ：

[root@localhost ~]# rpm -qa | grep -i mysql
mysql-server-5.1.73-5.el6_6.i686
mysql-libs-5.1.73-5.el6_6.i686
mysql-5.1.73-5.el6_6.i686
perl-DBD-MySQL-4.013-3.el6.i686

[root@localhost ~]# rpm -e --nodeps mysql-server-5.1.73-5.el6_6.i686
[root@localhost ~]# rpm -e --nodeps mysql-5.1.73-5.el6_6.i686
[root@localhost ~]# rpm -e --nodeps perl-DBD-MySQL-4.013-3.el6.i686
[root@localhost ~]# rpm -e --nodeps mysql-libs-5.1.73-5.el6_6.i686

3. 安装新的 mysql

cd /opt/mysql
ls -al

rpm -ivh xx
# i：安装
# v：显示安装进度
# h：显示安装过程

service mysqld status
# 查看 mysql 服务状态

• 在 /opt 目录下创建 mysql 目录，并上传 mysql 安装包
  

• 进入 /opt/mysql 目录，安装 mysql

[root@localhost ~]# cd /opt/mysql/
[root@localhost mysql]# ls -al
total 89216
drwxr-xr-x. 2 root root     4096 Mar  3 13:38 .
drwxr-xr-x. 4 root root     4096 Mar  3 13:38 ..
-rw-r--r--. 1 root root 20893788 Mar 11  2020 MySQL-client-5.6.48-1.el6.i686.rpm
-rw-r--r--. 1 root root 64038720 Mar 11  2020 MySQL-server-5.6.48-1.el6.i686.rpm
-rw-r--r--. 1 root root  2235116 Mar 11  2020 MySQL-shared-5.6.48-1.el6.i686.rpm
-rw-r--r--. 1 root root  4173024 Mar 11  2020 MySQL-shared-compat-5.6.48-1.el6.i686.rpm

[root@localhost mysql]# rpm -ivh MySQL-client-5.6.48-1.el6.i686.rpm 
warning: MySQL-client-5.6.48-1.el6.i686.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing...                ########################################### [100%]
   1:MySQL-client           ########################################### [100%]

[root@localhost mysql]# rpm -ivh MySQL-shared-5.6.48-1.el6.i686.rpm 
warning: MySQL-shared-5.6.48-1.el6.i686.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing...                ########################################### [100%]
   1:MySQL-shared           ########################################### [100%]

[root@localhost mysql]# rpm -ivh MySQL-shared-compat-5.6.48-1.el6.i686.rpm 
warning: MySQL-shared-compat-5.6.48-1.el6.i686.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing...                ########################################### [100%]
   1:MySQL-shared-compat    ########################################### [100%]

[root@localhost mysql]# rpm -ivh MySQL-server-5.6.48-1.el6.i686.rpm
warning: MySQL-server-5.6.48-1.el6.i686.rpm: Header V3 DSA/SHA1 Signature, key ID 5072e1f5: NOKEY
Preparing...                ########################################### [100%]
   1:MySQL-server           ########################################### [100%]
...... 初始化数据库 ......

• 验证 mysql 是否被安装成功，查看 mysql 服务状态

# mysql 安装成功，mysql 服务非启动状态
[root@localhost mysql]# service mysqld status
MySQL is not running[FAILED]

# mysql 安装失败，mysql 服务无法识别
[root@localhost mysql]# service mysqld status
mysql: unrecognized service

• 若 mysql 安装失败，卸载所有 mysql 相关包，重新安装 mysql

[root@localhost mysql]# service mysqld status
mysql: unrecognized service

[root@localhost mysql]# rpm -qa | grep -i mysql
mysql-libs-5.1.73-5.el6_6.i686
MySQL-shared-5.6.48-1.el6.i686
MySQL-client-5.6.48-1.el6.i686
MySQL-shared-compat-5.6.48-1.el6.i686

[root@localhost mysql]# rpm -e --nodeps MySQL-shared-5.6.48-1.el6.i686
[root@localhost mysql]# rpm -e --nodeps MySQL-client-5.6.48-1.el6.i686
[root@localhost mysql]# rpm -e --nodeps MySQL-shared-compat-5.6.48-1.el6.i686
[root@localhost mysql]# rpm -e --nodeps mysql-libs-5.1.73-5.el6_6.i686

[root@localhost mysql]# rpm -ivh MySQL-client-5.6.48-1.el6.i686.rpm
[root@localhost mysql]# rpm -ivh MySQL-shared-5.6.48-1.el6.i686.rpm
[root@localhost mysql]# rpm -ivh MySQL-shared-compat-5.6.48-1.el6.i686.rpm
[root@localhost mysql]# rpm -ivh MySQL-server-5.6.48-1.el6.i686.rpm

[root@localhost mysql]# service mysqld status
MySQL is not running[FAILED]

4. 配置 root 用户密码

service mysqld start
# 启动 mysql 服务
# status：状态
# start：启动
# stop：关闭
# restart：重启

cd /root
ls -al .mysql_secret
# 验证 .mysql_secret 是否存在

cat /root/.mysql_secret
# 查看 root 用户的密码

mysql -u root -p
# 进入 mysql 修改密码
set password for root@localhost=password('123456');
flush privileges;
# 修改密码，刷新授权表

• 启动 mysql 服务，查看 root 用户的密码：ROvVVC_2cf9jIXUX

[root@localhost ~]# service mysqld start
Starting MySQL.[  OK  ]

[root@localhost mysql]# cd /root
[root@localhost ~]# ls -al .mysql_secret
-rw-------. 1 root root 104 Apr 18 18:45 .mysql_secret

[root@localhost ~]# cat /root/.mysql_secret
# The random password set for the root user 
at Sun Apr 18 18:45:25 2021 (local time): ROvVVC_2cf9jIXUX

• 使用该密码，进入 mysql 修改密码，刷新授权表

[root@localhost ~]# mysql -u root -p
Enter password: ROvVVC_2cf9jIXUX
Welcome to the MySQL monitor.  

mysql> set password for root@localhost=password('123456');
Query OK, 0 rows affected (0.00 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

mysql> Ctrl-C -- exit!
Aborted

• 退出 mysql（Ctrl + C），再以新密码进入 mysql，验证密码是否修改成功

[root@localhost ~]# mysql -u root -p
Enter password: 123456
Welcome to the MySQL monitor.

到此，新的 Mysql 安装完成

5. 总结 Linux 重新安装 Mysql 的步骤

# 验证 mysql 是否安装
1、rpm -qa | grep -i mysql

# 卸载之前的 mysql 
2、 rpm -e --nodeps mysql-server-5.1.73-5.el6_6.i686
	rpm -e --nodeps mysql-5.1.73-5.el6_6.i686
	rpm -e --nodeps perl-DBD-MySQL-4.013-3.el6.i686
	rpm -e --nodeps mysql-libs-5.1.73-5.el6_6.i686

# 上传 mysql 安装包，安装新的 mysql
3、 cd /opt/mysql
	ls -al
	rpm -ivh MySQL-client-5.6.48-1.el6.i686.rpm
	rpm -ivh MySQL-shared-5.6.48-1.el6.i686.rpm
	rpm -ivh MySQL-shared-compat-5.6.48-1.el6.i686.rpm
	rpm -ivh MySQL-server-5.6.48-1.el6.i686.rpm
	
# 验证 mysql 是否安装成功，成功显示：MySQL is not running[FAILED]
4、service mysqld status

# 启动 mysql 服务，查看 root 用户的密码
# 使用该密码，进入 mysql 修改密码，刷新授权表
# 退出 mysql，再以新密码进入 mysql，验证密码是否修改成功
5、 service mysqld start
	cat /root/.mysql_secret
	mysql -u root -p 
		set password for root@localhost=password('123456');
		flush privileges;
	mysql -u root -p 
	
# mysql 服务命令
service mysqld status / start / stop / restart