Ubuntu Linux Change Hostname (computer name)

am a new Ubuntu Linux laptop user. I setup my computer name to ‘tom’ during installation but now I would like to change the computer name to ‘jerry’. Can you tell me how do I I remove tom and set it to jerry on Ubuntu Linux? How do I change the Ubuntu computer name from ‘ubuntu’ to ‘AvlinStar’?

You can use the hostname command to see or set the system’s host name. The host name or computer name is usually at system startup in /etc/hostname file. Open the terminal application and type the following command.

Display the current Ubuntu hostname

Simply type the following command:
$ hostname
Sample outputs:

Fig.01: Ubuntu Linux Show the hostname/computer name command

Ubuntu change hostname command

The procedure to change the computer name on Ubuntu Linux:

1. Type the following command to edit /etc/hostname using nano or vi text editor:
   sudo nano /etc/hostname
   Delete the old name and setup new name.
2. Next Edit the /etc/hosts file:
   sudo nano /etc/hosts
   Replace any occurrence of the existing computer name with your new one.
3. Reboot the system to changes take effect:
   sudo reboot

Sample outputs:

Gif 01: Ubuntu change the computer name demo

How to change the Ubuntu server hostname without a system restart?

Type the following commands:
$ sudo hostname new-server-name-here
Next edit the /etc/hostname file and update hostname:
$ sudo nano /etc/hostname
Finally, edit the /etc/hosts file and update the lines that reads your old-host-name:
$ sudo nano /etc/hosts
From:
127.0.1.1 old-host-name
To:
127.0.1.1 new-server-name-here
Save and close the file.

A note about hostnamectl command

Systemd based Linux distor such as Ubuntu Linux 16.04 LTS and above can simply use the hostnamectl command to rename hostname. To see current setting just type:
$ hostnamectl
Sample outputs:

Static hostname: nixcraft Icon name: computer-laptop Chassis: laptop Machine ID: 291893e6499e4d99891c3cf4b70a138b Boot ID: 9fda2365b77841649e40a141fde46537 Operating System: Ubuntu 17.10 Kernel: Linux 4.13.0-21-generic Architecture: x86-64

To change hostname from nixcraft to viveks-laptop, enter:
$ hostnamectl set-hostname viveks-laptop
$ hostnamectl

Sumber: https://www.cyberciti.biz/faq/ubuntu-change-hostname-command/