how to change hostname in ubuntu

C++
#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
hostnamectlsudo nano /etc/hostname
sudo nano /etc/hosts
sudo reboot# -l changes login name
# -d changes home directory
# -m copies over contents from old home directory
usermod -l <newname> -d /home/<newname> -m <oldname>

# NOTE: will not work if you are currently logged on as user
# - workaround by temporarily enabling root account and running above command there
# [sudo passwd root] 
# - after root account has been used to change username lock it using
# [sudo passwd -l root]Type the following commands:
$ sudo hostname new-server-name-here
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