Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

server2:/usr/local/bin # ./mysql -u root -p
Enter password:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

命令：
/usr/local/bin/mysqld_safe --user=mysql &

以安全模式启动