How do I change the hostname without a restart?

Solution 1:

It's easy. Just click the Gear icon (located at upper right corner of the screen), open "About this computer" screen (located at Gear icon ) and edit "Device name".

Or, in a terminal, use the following command:

sudo hostname your-new-name

This will set the hostname to your-new-name until you restart. See man hostname and How do I change the computer name? for further information. Do not use _ in your name.

Note

After a restart your changes in /etc/hostname will be used, so (as you said in the question), you should still use

sudo -H gedit /etc/hostname

(or some other editor) so that file contains the hostname.

To test that the file is set up correctly, run:

sudo service hostname start

You should also edit /etc/hosts and change the line which reads:

127.0.1.1     your-old-hostname

so that it now contains your new hostname. (This is required otherwise many commands will cease functioning.)

Solution 2:

Ubuntu 13.04 onwards

The hostnamectl command is part of the default installation on both Desktop and Server editions.

It combines setting the hostname via the hostname command and editing /etc/hostname. As well as setting the static hostname, it can set the "pretty" hostname, which is not used in Ubuntu. Unfortunately, editing /etc/hosts still has to be done separately.

hostnamectl set-hostname new-hostname

This command is part of the systemd-services package (which, as of Ubuntu 14.04, also includes the timedatectl and localectl commands). As Ubuntu migrates to systemd, this tool is the future.

Solution 3:

Without Restart

Changing the hostname or computer name in ubuntu without restart

Edit /etc/hostname and change to the new value,

nano /etc/hostname 

Edit /etc/hosts and change the old 127.0.1.1 line to your new hostname

127.0.0.1   localhost
127.0.1.1   ubuntu.local    ubuntu   # change to your new hostname/fqdn

Note : i have read it on a forum > Edit /etc/hosts and change the old 127.0.1.1 line to your new hostname (if you dont do this, you wont be able to use sudo anymore. If you hav e already done it, press ESC on the grub menu, choose recovery, and edit your host file to the correct settings)

Now after a reboot, your hostname will be the new one you chose

Without Reboot

To change without a reboot, you can just use hostname.sh after you edit /etc/hostname. You must keep both your host names in /etc/hosts (127.0.0.1 newhost oldhost) until you execute the command below:

sudo service hostname start

Note : Above command to make the change active. The hostname saved in this file (/etc/hostname) will be preserved on system reboot (and will be set using the same service).

Solution 4:

The default name was set when you were installing Ubuntu. You can easily change it to whatever you want in both Desktop & Server by editing the hosts and hostname files. Below is how:

1. Press CtrlAltt on keyboard to open the terminal. When it opens, run the below command: sudo hostname NEW_NAME_HERE

This will change the hostname until next reboot. The change won’t be visible immediately in your current terminal. Start a new terminal to see the new hostname.

2. To change the name permanently, run command to edit the host files:

   sudo -H gedit /etc/hostname and sudo -H gedit /etc/hosts

For Ubuntu server without a GUI, run sudo vi /etc/hostname and sudo vi /etc/hosts and edit them one by one. In both files, change the name to what you want and save them.

Finally, restart your computer to apply the changes.

Solution 5:

Cloud-init (Ubuntu 18+) hostname persistence

Whilst the above approaches (hostnamectl, etc/hostname, etc) work for immediate hostname change, with the advent of cloud-init - which can control setting of the hostname - amongst many other things. So it won't stick after a reboot if cloud-init is installed. If you want the change to stay after a reboot then you'll need to edit the cloud-init config files, disable cloud-init's hostname set/update module:

sudo sed 's/preserve_hostname: false/preserve_hostname: true/' /etc/cloud/cloud.cfg

or disable cloud-init entirely:

sudo touch /etc/cloud/cloud-init.disabled