Tuesday, December 22, 2009

How to change MySQL root password

Q. How can you change root password of MySQL when you've forgotten root password and when you know root password.

ANS:

I will try to explain the procedure to change MySQL root password in both scenarios.

When Forgotten Root Password

Step # 1: First of all stop MySQL.
Step # 2: You need to disable password prompt of MySQL. So start mysql MySQL with the --skip-grant-tables option so that it will not prompt for password.
Step # 3: Connect to MySQL using root user.
Step # 4: Setup new root password
Step # 5: Quit and then restart MySQL

The commands that you will use to achieve this are given below.

Step # 1 : First of all stop MySQL.

# /etc/init.d/mysql stop

OR
# service mysql stop

Step # 2 : Start MySQL without password prompt.

# /etc/init.d/mysql stop

Step # 3 : Connect to MySQL.
MySQL -uroot

Step # 4 : Setup new root password.

mysql> use mysql;
mysql> update user set password=PASSWORD("NEW-ROOT-PASSWORD") where User='root';
mysql> flush privileges;
mysql> quit


Step # 5 : Stop MySQL.

# /etc/init.d/mysql stop

OR

# service mysql stop

Step # 6 : Start MySQL and test with new password.
# /etc/init.d/mysql start
OR
# service mysql start

# mysql -u root -p

That's it and you have setup new root password in case you forgot root password.

When Root Password is known

If you never setup root password of MySQL then it doesn't require password to connect as root. To setup root password for first time, use mysqladmin command at shell prompt as given below:

$ mysqladmin -u root password NEWPASSWORD

But when you want to change existing root password then use following mysqladmin command at shell.

$ mysqladmin -u root -p'oldpassword' password newpass

Let suppose root password is zaeem and you want to change it to abc123 then command would look like

$ mysqladmin -u root -p'zaeem' password 'abc123'

I hope you find this article helpful.

Monday, December 21, 2009

How to take database backup in MySQL

Q. How to take database backup in MySQL

I will explain different options of taking database backup in MySQL server. Let support I have database 'TestDB' which I want to take backup of with different options.

# mysqldump -uroot -ppassword TestDB >TestDB.sql

If your database contains procedures and function then use -R flag and the modified command would be as follows;

# mysqldump -uroot -ppassword TestDB -R > TestDB.sql

What if you only want to take backup of table structures then commands will look as given below.


# mysqldump -uroot -ppassword -d TestDB > TestDB.sql

How to change password of Linux user (Non-root)

System administrators often needs to change password of system users. This article explains you how ti change password of Linux users. Let suppose you want to change password of user 'zaeem'. Simply open a shell and type following commands.

# passwd zaeem

The output of above command is;

Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully


I hope you can find this article helpful.

Friday, December 18, 2009

How to change root password of Linux

It is very easy to change root password of linux while being logged in as root. Just type command "passwd" on shell and press enter so it will ask to enter new password. That's it and you're done changing root password of Linux.