8.4. Using Hostnamectl

The hostnamectl tool is provided for administering the three separate classes of host names in use on a given system. The three classes of hostname are: static, pretty, and transient.

The static host name is the traditional hostname, which can be chosen by the user, and is stored in the /etc/hostname file. The “transient” hostname is a dynamic host name maintained by the kernel. It is initialized to the static host name by default, whose value defaults to “localhost”. It can be changed by DHCP or mDNS at runtime. The pretty hostname is a free-form UTF8 host name for presentation to the user.

Note

A host name can be a free-form string up to 64 characters in length, however it is recommended that the static and transient names consists only of 7 bit ASCII lower-case characters, no spaces or dots, and limits itself to the format allowed for DNS domain name labels, even though this is not a strict requirement. The hostnamectl tool will enforce the following: Static and transient host names to consist of a-z, A-Z, 0-9, “-”, “_” and “.” only, to not begin or end in a dot, and to not have two dots immediately following each other. The size limit of 64 charcters is enforced.

8.4.1. View all the Hostnames

To view all the current host names, enter the following command:

~]$ hostnamectl status

The status option is implied by default if no option is given.