centos7安装mysql时会得到一个系统给的初始密码，因此我们无法直接登录mysql，需要先对其进行修改
我安装的是mysql5.6
wget /mysql-community-release-el7-5.noarch.rpmsudo rpm -ivh mysql-community-release-el7-5.noarch.rpmyum install -y mysql mysql-server
在修改前要先启动mysql,并检查其运行状态
sudo systemctl start mysqldservice mysqld status
接着修改mysql密码
方法一：
grep 'temporary password' /var/log/mysqld.log
运行后会得到一个密码，这里我的centos7.4下没有反应，故尝试第二种方法
方法二：
该方法先修改mysql配置文件使其可以无密码登录，让后修改密码，之后便复原配置文件
修改/etc/f
vim /etc/f
配置文件添加skip-grant-tables
[root@VM_0_8_centos ~]# vim /etc/f# For advice on how to change settings please see# /doc/refman/5.6/en/server-configuration-defaults.html[mysqld]## Remove leading # and set to the amount of RAM for the most important data# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.# innodb_buffer_pool_size = 128M## Remove leading # to turn on a very important data integrity option: logging# changes to the binary log between backups.# log_bin## Remove leading # to set options mainly useful for reporting servers.# The server defaults are faster for transactions and fast SELECTs.# Adjust sizes as needed, experiment to find the optimal values.# join_buffer_size = 128M# sort_buffer_size = 2M# read_rnd_buffer_size = 2Mdatadir=/var/lib/mysqlsocket=/var/lib/mysql/mysql.sockskip-grant-tables 此处！！！！！！# Disabling symbolic-links is recommended to prevent assorted security riskssymbolic-links=0
保存后重启mysql
systemctl restart mysql
即可免密登录，命令行输入mysql直接登录
选择mysql数据库，输入下列命令重置密码，'new-password’即为所设置密码
USE mysql;mysql> UPDATE user SET Password = 'new-password' WHERE User = 'root';
修改完成后输入exit退出，重新回到/etc/f该文件删除之前添加语句即可完成
