ERROR 2002 (HY000): Can't connect server socket /tmp/mysql.sock
自己采用的解决方案：
启动MySQL数据库：
***@***-VirtualBox:~$ sudo /etc/init.d/mysql.server start
Starting MySQL
.... * The server quit without updating PID file (/usr/local/mysql/data/***-VirtualBox.pid).
针对以上错误，网上各种百度，各种谷歌都解决不了，还是提示上面的同样的错误
我采用下面的方法，竟然可以启动MySQL，但是又引发了其他的无法解决的error
################################## 方法如下 ##############################
按照网址：http://www.justin.my/2012/03/starting-mysql-error-the-server-quit-without-updating-pid-file/
竟然可以启动MySQL服务，如下：
***@***-VirtualBox:/etc$ sudo mv /etc/my.cnf /etc/my.cnf.old
***@***-VirtualBox:/etc$ sudo /etc/init.d/mysql.server start
Starting MySQL
.. *
但是，无法登陆了：
***@***-VirtualBox:/etc/mysql/conf.d$ sudo mysql -u root -p
Enter password:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
这个错误我用了各种办法无法解决，无奈把my.cnf的名称变回来：
***@***-VirtualBox:/etc$ sudo mv /etc/my.cnf.old /etc/my.cnf
####################################################################
解决方法：
查看错误日志，定位到日志最后几行：***@***-VirtualBox:/usr/local/mysql$ more ./data/***-VirtualBox.err
##### 日志内容 start #####
140928 08:52:32 mysqld_safe mysqld from pid file /usr/local/mysql/data/ga
oyu-VirtualBox.pid ended
140928 10:53:01 mysqld_safe Starting mysqld daemon with databases from /u
sr/local/mysql/data
140928 10:53:01 [Note] Plugin 'FEDERATED' is disabled.
140928 10:53:01 InnoDB: The InnoDB memory heap is disabled
140928 10:53:01 InnoDB: Mutexes and rw_locks use InnoDB's own implementat
ion
140928 10:53:01 InnoDB: Compressed tables use zlib 1.2.3
140928 10:53:01 InnoDB: Using Linux native AIO
140928 10:53:01 InnoDB: Initializing buffer pool, size = 128.0M
140928 10:53:01 InnoDB: Completed initialization of buffer pool
140928 10:53:01 InnoDB: highest supported file format is Barracuda.
140928 10:53:01 InnoDB: Waiting for the background threads to start
140928 10:53:02 InnoDB: 5.5.39 started; log sequence number 44664632
140928 10:53:02 [ERROR] /usr/local/mysql/bin/mysqld: unknown variable 'de
fault-character-set=utf8'
140928 10:53:02 [ERROR] Aborting
140928 10:53:02 InnoDB: Starting shutdown...
140928 10:53:03 InnoDB: Shutdown completed; log sequence number 44664632
140928 10:53:03 [Note] /usr/local/mysql/bin/mysqld: Shutdown complete
140928 10:53:03 mysqld_safe mysqld from pid file /usr/local/mysql/data/ga
oyu-VirtualBox.pid ended
##### 日志内容 end #####
记得自己为了解决同事的字符编码问题，把自己机器上面的配置文件修改过：修改了/etc/my.cnf里面的【mysqld】的字符设置，在修改回来，试试看，修改方法如下：
把 [client] [mysqld] [mysql]里面的 default-character-set=utf8 都注释掉
发现好使了，可以成功登陆MySQL了。
***@***-VirtualBox:/usr/local/mysql$ sudo /etc/init.d/mysql.server start
Starting MySQL
.... *
***@***-VirtualBox:/usr/local/mysql$ sudo mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.5.39-log MySQL Community Server (GPL)
Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
来自 “ ITPUB博客 ” ，链接：https://blog.itpub.net/26435490/viewspace-1283327/ ，如需转载，请注明出处，否则将追究法律责任。
