MySQL installation, uninstallation, initial password setting and general commands of Linux

1. install MySQL

Update source and install MySQL：

sudo apt-get update  #  Update source 
sudo apt-get install mysql-server #  install mysql

Check MySQL Is the installation successful ：
because mysql After installation , It will start automatically, so you can check the running status , Verify that the installation was successful .

systemctl status mysql ##  see mysql state 

systemctl Use of commands and view of service status

mysql --version ##  see mysql edition 

It can be verified by the above two methods mysql Is the installation successful .

2. uninstall MySQL

sudo rm /var/lib/mysql/ -R      #  Delete database directory 
sudo rm /etc/mysql/ -R          #  Delete startup script 、 Configuration files, etc 
sudo apt-get autoremove mysql* --purge      #  uninstall mysql All the files 
sudo apt-get remove apparmor     #  This apparmor It's pretending mysql-server In fashion , Safety related 
dpkg -l |grep ^rc|awk '{print $2}' |sudo xargs dpkg -P    #  Clean up the residue mysql file 

3. Check the initial account and password

3.1 Check the initial account and password

Because when installing , No password set ,mysql The account and password will be automatically generated , Use the following command to view ：

sudo cat /etc/mysql/debian.cnf 

result ：

3.2 Change account and password

1. Use the initialization account password to enter mysql, Everyone's initialization password is different ：

mysql -u  debian-sys-maint -p

Successfully logged in , Here's the picture ：

2. Set up root Password ：
user Medium root It's an account ,password It's a password ：bianbian123

update mysql.user set authentication_string=password("88888888"),plugin='mysql_native_password' where user='root';

The results are shown in the following figure ：

3. sign out mysql

flush privileges; #  Hit enter , Update and modify 
quit;    #  Hit enter , sign out 

4. restart mysql, And login
restart ：

 systemctl restart  mysql

Sign in ：

 mysql -u root -p88888888

4. Normal operation

systemctl start  mysql #  Turn on mysql
systemctl stop  mysql #  stop it mysql
systemctl restart  mysql #  restart mysql
systemctl status  mysql # mysql Running state 

Reference resources :

https://blog.csdn.net/cruiserblog/article/details/106934570
https://www.it610.com/article/1304140137831108608.htm
http://www.manongjc.com/detail/11-tzeibqtfcoijnye.html
https://www.cnblogs.com/benjamin77/p/8681763.html
https://www.cnblogs.com/cpl9412290130/p/9583868.html