启动mysql 报错：

ERROR 2002 (HY000): Can’t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock’ (2)

1、先查看 /etc/rc.d/init.d/mysqld status 看看mysql是否已经启动.
另外看看是不是权限问题.

2、确定你的mysql.sock是不是在那个位置，
mysql -u 你的mysql用户名 -p -S /var/lib/mysql/mysql.sock

3、试试：service mysqld start

4、如果是权限问题，则先改变权限 #chown -R mysql:mysql /var/lib/mysql

[root@localhost ~]# /etc/init.d/mysqld start
启动 MySQL： [ 确定 ]
[root@localhost ~]# mysql -u root -p

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)
原因是，/var/lib/mysql 的访问权限问题。

shell> chown -R mysql:mysql /var/lib/mysql

接着启动服务器

shell> /etc/init.d/mysql start

服务器正常启动后察看 /var/lib/mysql 自动生成mysql.sock文件。

但是我的问题仍然没有得到解决。

问题终于解决：
方法： 修改/etc/my.conf:
[mysqld] 
datadir=/usr/local/mysql/data 
socket=/var/lib/mysql/mysql.sock

[mysql.server] 
user=mysql 
basedir=/usr/local/mysql

If there is not currently a section called [client], add one at the bottom of the file and copy the socket= line under the [mysqld] section such as:

[client] 
socket=/var/lib/mysql/mysql.sock

发现依旧如此，运行/etc/init.d/mysql start报错：Starting MySQLCouldn't find MySQL manager or server 
是mysqld服务没启，运行/usr/local/mysql/bin/mysqld_safe &

问题解决。
執行 PHP 時出現類似這樣的錯誤訊息：
Warning: MySQL Connection Failed: Can't connect to local MySQL server through socket '/tmp/mysql.sock' (111) in /home/httpd/html/show.php on line 9
請將 /tmp/mysql.sock link 到 /var/lib/mysql 目錄裡即可：
linux# ln -s /var/lib/mysql/mysql.sock /tmp/mysql.sock