why cannot cd mysql datadir?
 

here is mysql datadir:
mei@ubuntu:~$ ls -ld /var/lib/mysql
drwx------ 5 mysql mysql 4096 2011-08-04 09:35 /var/lib/mysql

mei@ubuntu:~$ cd /var/lib/mysql
bash: cd: /var/lib/mysql: Permission denied

mei@ubuntu:~$ sudo cd /var/lib/mysql
sudo: cd: command not found

mei@ubuntu:~$ sudo cp -rf /var/lib/mysql /mysql1
mei@ubuntu:~$ cd /mysql1

mei@ubuntu:/mysql1$ ls -la
total 12
drwxr-xr-x 3 mysql mysql 4096 2011-08-04 10:04 .
drwxr-xr-x 24 root root 4096 2011-08-04 09:20 ..
drwx------ 5 root root 4096 2011-08-04 10:04 mysql

mei@ubuntu:/mysql1$ cd mysql
bash: cd: mysql: Permission denied

I need help! thanks

The directory has read, write and execute permissions for the superuser only. Either log in as root with su -, or change the permissions on the directory: