linux change hostname code example

Example 1: how to change hostname in ubuntu

#1- Delete the old name and setup new name
sudo hostnamectl set-hostname newHostname

#2- Edit the /etc/hosts file:
sudo nano /etc/hosts

#3- Reboot the system 
sudo reboot

#4- To check the new hostname
hostnamectl

Example 2: centos change hostname

# hostnamectl set-hostname your-new-hostname

Example 3: linux change username

# login as root and make sure that there are no active processes for user
usermod -l NEW_USERNAME OLD_USERNAME
# if user is running kill user w the following command
userUID=$(id -u OLD_USERNAME) && pkill -U $userUID

Example 4: linux change hostname

sudo nano /etc/hostname
sudo nano /etc/hosts
sudo reboot