默认情况下Linux主机的名称是localhost如：
[root@localhost ~]# hostname
localhost.localdomain
修改如下：
[root@localhost ~]# vim /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
把中间的localhost.localdomain修改成自己的名称：kiccleaf
127.0.0.1 localhost kiccleaf localhost4 localhost4.localdomain4
::1 localhost kiccleaf localhost6 localhost6.localdomain6
[root@localhost ~]# vim /etc/hostname
把localhost名称修改成自己的名称：kiccleaf
重启一下系统
[root@localhost ~]# reboot
Connecting to *.*.*.*:22...
Connection established.
To escape to local shell, press Ctrl+Alt+].
Welcome to CentOS 8
_ _ _ ___
| | (_) | | / __)
| | _ _ ____ ____| | _____ _____ _| |__
| |_/ ) |/ ___) ___) || ___ (____ (_ __)
| _ (| ( (__( (___| || ____/ ___ | | |
|_| \_)_|\____)____)\_)_____)_____| |_|
Last login: Tue Aug 25 11:57:55 2020 from *.*.*.*
[root@kiccleaf ~]# hostname
kiccleaf
FreeBSD修改名称比较简单
root@localhost:~ # vim /etc/rc.conf
hostname="kiccleaf"
root@localhost:~ # reboot
#重启后连接显示
Connecting to *.*.*.*:22...
Connection established.
To escape to local shell, press Ctrl+Alt+].
Last login: Mon Aug 24 18:06:00 2020 from *.*.*.*
FreeBSD 12.1-RELEASE r354233 GENERIC
Welcome to FreeBSD!
_ _ _ ___
| | (_) | | / __)
| | _ _ ____ ____| | _____ _____ _| |__
| |_/ ) |/ ___) ___) || ___ (____ (_ __)
| _ (| ( (__( (___| || ____/ ___ | | |
|_| \_)_|\____)____)\_)_____)_____| |_|
root@kiccleaf:~ # uname -a
FreeBSD kiccleaf 12.1-RELEASE FreeBSD 12.1-RELEASE r354233 GENERIC amd64