How to Change the Hostname of CentOS or RedHat Linux systems?

We can change the hostname of a machine by several ways. I am mentioning two ways to change the hostname.

Method 1 :- Editting /etc/sysconfig/network file

1. Open the terminal or Login with putty.exe as root user (if you are working remotely)
2. Goto /etc/sysconfig/
3. Type nano network
4. Change the HOSTNAME to your preferred machine name
5. Press Cntrl+X
6. Save the configuration by pressing Y
7. Log off or reboot

Method 2:- Editting  /proc/sys/kernel/hostname file

1. Open the terminal or Login with putty.exe as root user (if you are working remotely)
2. Goto /proc/sys/kernel/
3. Type nano hostname
4. Change the HOSTNAME to your preferred machine name
5. Press Cntrl+X
6. Save the configuration by pressing Y
7. Close the terminal and login again

In this method, no reboot is required to get the change in effect

Note: Add the ipaddress and new hostname to /etc/hosts file also