hostname and hostnamectl Command

In your shell, you might see your host name but it requires a special configuration for your shell prompt. This is not the best way for us to determine our host name. Why? First, your shell might not be configured to show your host name. Or even misconfigured to show it wrong! Second, how can you get your Linux host name information and use it inside a shell script?

To learn your Linux hostname, you can use hostname command.

linux hostname command

ali@zion:~$ hostname
zion

You can use hostname newhostname to change your hostname, can you?

You might be asking "Why my host name keeps changing after reboot in Linux?". Well, because hostname command changes your host name temporarily. If this is what you want, go for it.

How to Change Host Name Permanently in Linux?

To achieve this, we'll use hostnamectl command.

linux hostnamectl command

root@localhost ~]# hostnamectl
   Static hostname: localhost.localdomain
         Icon name: computer-vm
           Chassis: vm
        Machine ID: afcc248f7e79e74fae68fa641b940b71
           Boot ID: c40fb2c23ab54d6d9ffbec52cd127851
    Virtualization: kvm
  Operating System: CentOS Linux 7 (Core)
       CPE OS Name: cpe:/o:centos:centos:7
            Kernel: Linux 3.10.0-1160.41.1.el7.x86_64
      Architecture: x86-64

So, what are these? Icon name is used my some graphical applications to visualize your host. Chassis works like the same. But it determines the host type like desktop, tablet, server, embedded etc. Now let's change the host name and see how it goes. You can change your host name in Linux via hostnamectl set-hostname new_host_name command:

linux hostnamectl command

root@localhost ~]# hostnamectl set-hostname "Jack's Laptop"
root@localhost ~]# hostnamectl
   Static hostname: jackslaptop
   Pretty hostname: Jack's Laptop
         Icon name: computer-vm
           Chassis: vm
        Machine ID: afcc248f7e79e74fae68fa641b940b71
           Boot ID: c40fb2c23ab54d6d9ffbec52cd127851
    Virtualization: kvm
  Operating System: CentOS Linux 7 (Core)
       CPE OS Name: cpe:/o:centos:centos:7
            Kernel: Linux 3.10.0-1160.41.1.el7.x86_64
      Architecture: x86-64

As you can see, the output has changed. Now we can see a "Pretty hostname". Pretty hostname is a name that you want to see in your computer. It's a bit flexible. Uppercase, lowercase, spaces and even a special character included in this host name. This is a high-level host name. On the other hand, "Static hostname" is used to initialize the kernel host name at boot. Your static host name resides at /etc/hostname file.

How to Change Some Other Host Properties in Linux?

Sometimes the host name itself might not be enough to address a computer. Hence you might want to give some additional info:

linux change host information

root@localhost ~]# hostnamectl set-hostname "Blog Web Server (Apache)"
root@localhost ~]# hostnamectl set-deployment development
root@localhost ~]# hostnamectl set-location "Amsterdam DC AX21 3rd Shelf"
root@localhost ~]# hostnamectl set-chassis server
root@localhost ~]# hostnamectl status
   Static hostname: blogwebserverapache
   Pretty hostname: Blog Web Server (Apache)
         Icon name: computer-server
           Chassis: server
        Deployment: development
          Location: Amsterdam DC AX21 3rd Shelf
        Machine ID: afcc248f7e79e74fae68fa641b940b71
           Boot ID: c40fb2c23ab54d6d9ffbec52cd127851
    Virtualization: kvm
  Operating System: CentOS Linux 7 (Core)
       CPE OS Name: cpe:/o:centos:centos:7
            Kernel: Linux 3.10.0-1160.41.1.el7.x86_64
      Architecture: x86-64

We can use hostnamectl set-deployment to set the deployment mode like "staging", "production", "development" etc. By using hostnamectl set-location, we can address the physical location of a machine. hostnamectl set-chassis can help us to set the device's chassis type. When we check the host name information of our Linux machine via hostnamectl status; we can easily say that this is a server located in Amsterdam Data Center AX21 cabinet 3rd shelf, used for development purposes and runs an Apache web server for our blog.

All of these information are stored in /etc/machine-info file.