1. ubuntu@shanghai:~ $ sudo ln -s /tmp/mysql.sock /var/mysql/mysql.sock
    2. ln: failed to create symbolic link '/var/mysql/mysql.sock': No such file or directory
    3. ubuntu@shanghai:~ $ sudo mkdir /var/mysql
    4. ubuntu@shanghai:~ $ sudo ln -s /tmp/mysql.sock /var/mysql/mysql.sock
    5. ubuntu@shanghai:~ $ mysql
    7. Command 'mysql' not found, but can be installed with:
    9. sudo apt install mysql-client-core-5.7   
    10. sudo apt install mariadb-client-core-10.1
    12. ubuntu@shanghai:~ $ cd /usr/local/bin/
    13. ubuntu@shanghai:/usr/local/bin $ ./mysql
    14. -bash: ./mysql: No such file or directory
    15. ubuntu@shanghai:/usr/local/bin $ cd ..
    16. ubuntu@shanghai:/usr/local $ cd mysql8/
    17. ubuntu@shanghai:/usr/local/mysql8 $ ls
    18. bin  data  docs  include  lib  LICENSE  man  README  share  support-files
    19. ubuntu@shanghai:/usr/local/mysql8 $ cd bin/
    20. ubuntu@shanghai:/usr/local/mysql8/bin $ ls
    21. ibd2sdi         myisamlog          mysqlcheck           mysqldump                  mysqlslap
    22. init.log        myisampack         mysql_config         mysqldumpslow              mysql_ssl_rsa_setup
    23. innochecksum    my_print_defaults  mysql_config_editor  mysqlimport                mysql_tzinfo_to_sql
    24. lz4_decompress  mysql              mysqld               mysqlpump                  mysql_upgrade
    25. myisamchk       mysqladmin         mysqld_multi         mysql_secure_installation  perror
    26. myisam_ftdump   mysqlbinlog        mysqld_safe          mysqlshow                  zlib_decompress
    27. ubuntu@shanghai:/usr/local/mysql8/bin $ ./mysql
    28. ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)
    29. ubuntu@shanghai:/usr/local/mysql8/bin $ systemctl status mysql
    30. ● mysql.server.service - LSB: start and stop MySQL
    31.    Loaded: loaded (/etc/init.d/mysql.server; generated)
    32.    Active: active (exited) since Wed 2020-09-23 14:20:49 CST; 15min ago
    33.      Docs: man:systemd-sysv-generator(8)
    34.   Process: 5658 ExecStart=/etc/init.d/mysql.server start (code=exited, status=0/SUCCESS)
    36. Sep 23 14:20:48 shanghai systemd[1]: Starting LSB: start and stop MySQL...
    37. Sep 23 14:20:48 shanghai mysql.server[5658]: /etc/init.d/mysql.server: line 239: my_print_defaults: command not fo
    38. Sep 23 14:20:49 shanghai mysql.server[5658]: /etc/init.d/mysql.server: line 259: cd: /usr/local/mysql: No such fil
    39. Sep 23 14:20:49 shanghai mysql.server[5658]: Starting MySQL * Couldn't find MySQL server (/usr/local/mysql/bin/mys
    40. Sep 23 14:20:49 shanghai systemd[1]: Started LSB: start and stop MySQL.
    41. ubuntu@shanghai:/usr/local/mysql8/bin $ ss -ntlp
    42. State      Recv-Q      Send-Q                                 Local Address:Port            Peer Address:Port     
    43. LISTEN     0           128                                        127.0.0.1:43145                0.0.0.0:*        
    44. LISTEN     0           32                                      10.215.178.1:53                   0.0.0.0:*        
    45. LISTEN     0           128                                    127.0.0.53%lo:53                   0.0.0.0:*        
    46. LISTEN     0           128                                          0.0.0.0:22                   0.0.0.0:*        
    47. LISTEN     0           50                                                 *:8080                       *:*        
    48. LISTEN     0           32                          [fd42:d7a9:43ea:5f86::1]:53                      [::]:*        
    49. LISTEN     0           32                [fe80::b007:37ff:fe44:5d15]%lxdbr0:53                      [::]:*        
    50. ubuntu@shanghai:/usr/local/mysql8/bin $ ./mysql -S /var/mysql/my
    51. mysql.sock
    52. ubuntu@shanghai:/usr/local/mysql8/bin $ ./mysql -S /var/mysql/mysql.sock 
    53. ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/mysql/mysql.sock' (2)
    54. ubuntu@shanghai:/usr/local/mysql8/bin $ ./mysql -S /tmp/mysql.sock
    55. ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)
    56. ubuntu@shanghai:/usr/local/mysql8/bin $ systemctl status mysql
    57. ● mysql.server.service - LSB: start and stop MySQL
    58.    Loaded: loaded (/etc/init.d/mysql.server; generated)
    59.    Active: active (exited) since Wed 2020-09-23 14:20:49 CST; 17min ago
    60.      Docs: man:systemd-sysv-generator(8)
    61.   Process: 5658 ExecStart=/etc/init.d/mysql.server start (code=exited, status=0/SUCCESS)
    63. Sep 23 14:20:48 shanghai systemd[1]: Starting LSB: start and stop MySQL...
    64. Sep 23 14:20:48 shanghai mysql.server[5658]: /etc/init.d/mysql.server: line 239: my_print_defaults: command not found
    65. Sep 23 14:20:49 shanghai mysql.server[5658]: /etc/init.d/mysql.server: line 259: cd: /usr/local/mysql: No such file or directory
    66. Sep 23 14:20:49 shanghai mysql.server[5658]: Starting MySQL * Couldn't find MySQL server (/usr/local/mysql/bin/mysqld_safe)
    67. Sep 23 14:20:49 shanghai systemd[1]: Started LSB: start and stop MySQL.
    68. ubuntu@shanghai:/usr/local/mysql8/bin $ cd ..
    69. ubuntu@shanghai:/usr/local/mysql8 $ ls
    70. bin  data  docs  include  lib  LICENSE  man  README  share  support-files
    71. ubuntu@shanghai:/usr/local/mysql8 $ cd ..
    72. ubuntu@shanghai:/usr/local $ s
    73. s: command not found
    74. ubuntu@shanghai:/usr/local $ ls
    75. bin  etc  games  include  lib  man  mysql8  qcloud  sbin  share  src  yd.socket.server
    76. ubuntu@shanghai:/usr/local $ mv mysql8/ mysql
    77. mv: cannot move 'mysql8/' to 'mysql': Permission denied
    78. ubuntu@shanghai:/usr/local $ sudo mv mysql8/ mysql
    79. ubuntu@shanghai:/usr/local $ 
    80. ubuntu@shanghai:/usr/local $ 
    81. ubuntu@shanghai:/usr/local $ 
    82. ubuntu@shanghai:/usr/local $ sudo systemctl restart mysql
    83. ubuntu@shanghai:/usr/local $ ss -ntlp
    84. State         Recv-Q          Send-Q                                         Local Address:Port                    Peer Address:Port         
    85. LISTEN        0               128                                                127.0.0.1:43145                        0.0.0.0:*            
    86. LISTEN        0               32                                              10.215.178.1:53                           0.0.0.0:*            
    87. LISTEN        0               128                                            127.0.0.53%lo:53                           0.0.0.0:*            
    88. LISTEN        0               128                                                  0.0.0.0:22                           0.0.0.0:*            
    89. LISTEN        0               70                                                         *:33060                              *:*            
    90. LISTEN        0               128                                                        *:3306                               *:*            
    91. LISTEN        0               50                                                         *:8080                               *:*            
    92. LISTEN        0               32                                  [fd42:d7a9:43ea:5f86::1]:53                              [::]:*            
    93. LISTEN        0               32                        [fe80::b007:37ff:fe44:5d15]%lxdbr0:53                              [::]:*            
    94. ubuntu@shanghai:/usr/local $ cd