在centos7系统中安装mysql后，启动mysql后报错（mysql版本是5.5.48），怎么解决啊？

如图所示，启动MySQL错误，提示缺少相应的pid文件。

2MyLinux[正在运行]-OracleVMVirtualBox 口 X
        usr/bin/perlisneeded bumuslL-serwer-5.5.48-1.1inux.6.X8664
[rootelocalhostopt]#rpm-ivh--nodeps MySQL-server-5.5.48-1.1inux2.6.×86_64.rpm
 arning：MySQL-server-5.5.48-1.1inux2.6.×86_64.rpm:Header V3 DSA/SHA1 Signature， keu ID 5072e1f5：
IREY
  baring..
Jndating/ installin
   1:MuStL-ser er-5.5.48-1.1inux2.6
22011114:37:30Note]/usr/sbin/mysgld（mysgld 5.5.48）starting asprocess 3939
22011114:37:30[Note]
PLEASE REMEMBER TO SET A PASSLORD FOR THE MySQL root USER！
To do so，start the server,then issue the follouing commands:
 ISr/bin/mysqladmin -h localhost.localdomain password new-passuord
Aternatively you can run：
 lsr/bin/mysgl_secure_installation
 hich will also give you the option of removing the test
latabases and anonymous user created by default. This is
trongly recomnended for production servers.
                       instructions.
 ootelocaIhost opt]#rpm -1uh -nodeps MySQL-client-5.5.48-1.1inux2.6.×86_64.rpm
                                                                                 keu ID5072e1f5：
KEY
 eparing
Jpdating/installing
  1:muS0L-client-5.5.48-1.1inux2.6
rootdlocalhost optl# service musql start
Starting MySUL.D ERROR! The server quit without updating PID file （/Var/lib/mysql/localhost.localdoma
in.pid）.
rootelocalhostopt]#
                                                                                 SRight Ctrl

报错提示你，由于PID造成，不过在5.5中，处理方法，没看到你更具体的日志，那你参考一下文法来尝试：
https://blog.csdn.net/ls_wifi/article/details/108291290
https://www.cnblogs.com/weibanggang/p/11230528.html
权限的话：https://blog.csdn.net/orichisonic/article/details/47021379