This comprehensive Linux guide expects that you run the following commands as root user but if you decide to run the commands as a different user then ensure that the user has sudo access and that you precede each of the privileged commands with sudo

A computer hostname represents a unique name that gets assigned to a computer in a network in order to uniquely identify that computer in that specific network.

During the installation of the Debian 9, the default hostname is set as “localhost”. But if you want to change the hostname to your own choice, you can follow the instructions in this tutorial. We will guide you to change the hostaname of your Debian 9.

Displaying Current Hostname

You can display the current hostname of the system by running the following command

root@codesposts:~$ hostnamectl

   Static hostname: localhost
         Icon name: computer-vm
           Chassis: vm
        Machine ID: ceb8b579410b472899a95049f8a61e05
           Boot ID: 3f73eea15fb34a38937488149143d9d3
    Virtualization: kvm
  Operating System: Debian GNU/Linux 9
            Kernel: Linux 4.13.0-32-amd64
      Architecture: x86-64

Instructions To Change Hostname

To change your current hostname to a new one, you can follow the instructions below

Changing Hostname Using hostnamectl Command

Run the following command to change your hostname.

root@codesposts:~$ hostnamectl set-hostname codesposts

Replace the “codesposts” with your new hostname.

The hostnamectl command does not produce output in case of successful execution.

Editing /etc/hosts File

After that, edit the file /etc/hosts using nano command.

root@codesposts:~$ nano /etc/hosts

Replace any occurence of the old hostname in that file with your new hostname and then save the file and exit.

Verification Of New Hostname

You can verify the new hostname by running the following command

root@codesposts:~$ hostnamectl

   Static hostname: codespsosts
         Icon name: computer-vm
           Chassis: vm
        Machine ID: ceb8b579410b472899a95049f8a61e05
           Boot ID: 3f73eea15fb34a38937488149143d9d3
    Virtualization: kvm
  Operating System: Debian GNU/Linux 9
            Kernel: Linux 4.13.0-32-amd64
      Architecture: x86-64