Change Mysql root password on Centos or Redhat RHEL

1. Default mysql password is “null” so we can access to mysql without password

[root@Centos6 ~]# mysql -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.1.66 Source distributionCopyright (c) 2000, 2012, 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>

2. Set root password

[root@Centos6 ~]# mysqladmin -u root password P@ssw0rd
[root@Centos6 ~]#

3. Change root password

[root@Centos6 ~]# mysqladmin -u root -p’P@ssw0rd’ password newP@ssw0rd
[root@Centos6 ~]#

4. Login to mysql with new password

[root@Centos6 ~]# mysql -p
Enter password: newP@ssw0rd
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.1.66 Source distributionCopyright (c) 2000, 2012, 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>