systemd hostname 5 hostname Local hostname configuration file /etc/hostname The /etc/hostname file configures the name of the local system that is set during boot using the sethostname2 system call. It should contain a single newline-terminated hostname string. Comments (lines starting with a `#') are ignored. The hostname may be a free-form string up to 64 characters in length; however, it is recommended that it consists only of 7-bit ASCII lower-case characters and no spaces or dots, and limits itself to the format allowed for DNS domain name labels, even though this is not a strict requirement. You may use hostnamectl1 to change the value of this file during runtime from the command line. Use systemd-firstboot1 to initialize it on mounted (but not booted) system images. The simple configuration file format of /etc/hostname originates from Debian GNU/Linux. systemd1, sethostname2, hostname1, hostname7, machine-id5, machine-info5, hostnamectl1, systemd-hostnamed.service8, systemd-firstboot1