[root@bogon ~]# hostnamectl set-hostname yz219.seabox.com
[root@bogon ~]# hostnamectl
   Static hostname: yz219.seabox.com
……
  Operating System: Red Hat Enterprise Linux Server 7.6 (Maipo)
       CPE OS Name: cpe:/o:redhat:enterprise_linux:7.6:GA:server
            Kernel: Linux 3.10.0-957.el7.x86_64
      Architecture: x86-64
[root@bogon ~]# cat /etc/hostname
yz219.seabox.com