查看主机名

方式一

echo @HOSTNAME 或者hostname

方式二

hostnamectl

[root@localhost ~]# hostnamectlStatic hostname: localhost.localdomainTransient hostname: localhostIcon name: computer-vmChassis: vmMachine ID: f5b4422ae39d4e5ab2e0fc32018cc6feBoot ID: f44ad9cf36b84812b4ab0956d1a3216dVirtualization: vmwareOperating System: CentOS Linux 7 (Core)CPE OS Name: cpe:/o:centos:centos:7Kernel: Linux 3.10.0-1160.90.1.el7.x86_64Architecture: x86-64[root@localhost ~]#

其中：

Static hostname，静态主机名

Transient hostname，临时主机名

查看静态主机名用hostnamectl,查看临时主机名用hostname

修改主机名

修改主机名需要两步：

1. 修改主机名

2. 修改下/etc/hosts中的对应关系

特别说明下：

修改主机名后，如果不修改/etc/hosts中的对应关系，从本地ping 主机名的时候会ping主机的外网地址，修改后，ping的是127.0.0.1.解析的过程会快一些

修改前：

[root@combo73 ~]# ping combo73PING combo73 (192.168.0.73) 56(84) bytes of data.64 bytes from localhost (192.168.0.73): icmp_seq=1 ttl=64 time=0.041 ms64 bytes from localhost (192.168.0.73): icmp_seq=2 ttl=64 time=0.043 ms64 bytes from localhost (192.168.0.73): icmp_seq=3 ttl=64 time=0.062 ms64 bytes from localhost (192.168.0.73): icmp_seq=4 ttl=64 time=0.061 ms64 bytes from localhost (192.168.0.73): icmp_seq=5 ttl=64 time=0.056 ms64 bytes from localhost (192.168.0.73): icmp_seq=6 ttl=64 time=0.064 ms64 bytes from localhost (192.168.0.73): icmp_seq=7 ttl=64 time=0.058 ms64 bytes from localhost (192.168.0.73): icmp_seq=8 ttl=64 time=0.058 ms64 bytes from localhost (192.168.0.73): icmp_seq=9 ttl=64 time=0.627 ms64 bytes from localhost (192.168.0.73): icmp_seq=10 ttl=64 time=0.058 ms64 bytes from localhost (192.168.0.73): icmp_seq=11 ttl=64 time=0.094 ms64 bytes from localhost (192.168.0.73): icmp_seq=12 ttl=64 time=0.064 ms64 bytes from localhost (192.168.0.73): icmp_seq=13 ttl=64 time=0.056 ms64 bytes from localhost (192.168.0.73): icmp_seq=14 ttl=64 time=0.062 ms64 bytes from localhost (192.168.0.73): icmp_seq=15 ttl=64 time=0.057 ms64 bytes from localhost (192.168.0.73): icmp_seq=16 ttl=64 time=0.054 ms64 bytes from localhost (192.168.0.73): icmp_seq=17 ttl=64 time=0.087 ms64 bytes from localhost (192.168.0.73): icmp_seq=18 ttl=64 time=0.071 ms64 bytes from localhost (192.168.0.73): icmp_seq=19 ttl=64 time=0.068 ms64 bytes from localhost (192.168.0.73): icmp_seq=20 ttl=64 time=0.066 ms64 bytes from localhost (192.168.0.73): icmp_seq=21 ttl=64 time=0.053 ms^C--- combo73 ping statistics ---21 packets transmitted, 21 received, 0% packet loss, time 24161msrtt min/avg/max/mdev = 0.041/0.088/0.627/0.121 ms

修改后：

[root@combo73 ~]# ping combo73PING combo73 (127.0.0.1) 56(84) bytes of data.64 bytes from combo73 (127.0.0.1): icmp_seq=1 ttl=64 time=0.029 ms64 bytes from combo73 (127.0.0.1): icmp_seq=2 ttl=64 time=0.058 ms64 bytes from combo73 (127.0.0.1): icmp_seq=3 ttl=64 time=0.059 ms64 bytes from combo73 (127.0.0.1): icmp_seq=4 ttl=64 time=0.046 ms64 bytes from combo73 (127.0.0.1): icmp_seq=5 ttl=64 time=0.057 ms64 bytes from combo73 (127.0.0.1): icmp_seq=6 ttl=64 time=0.053 ms64 bytes from combo73 (127.0.0.1): icmp_seq=7 ttl=64 time=0.053 ms64 bytes from combo73 (127.0.0.1): icmp_seq=8 ttl=64 time=0.054 ms64 bytes from combo73 (127.0.0.1): icmp_seq=9 ttl=64 time=0.053 ms64 bytes from combo73 (127.0.0.1): icmp_seq=10 ttl=64 time=0.046 ms64 bytes from combo73 (127.0.0.1): icmp_seq=11 ttl=64 time=0.045 ms64 bytes from combo73 (127.0.0.1): icmp_seq=12 ttl=64 time=0.055 ms64 bytes from combo73 (127.0.0.1): icmp_seq=13 ttl=64 time=0.054 ms64 bytes from combo73 (127.0.0.1): icmp_seq=14 ttl=64 time=0.062 ms64 bytes from combo73 (127.0.0.1): icmp_seq=15 ttl=64 time=0.148 ms64 bytes from combo73 (127.0.0.1): icmp_seq=16 ttl=64 time=0.065 ms64 bytes from combo73 (127.0.0.1): icmp_seq=17 ttl=64 time=0.057 ms64 bytes from combo73 (127.0.0.1): icmp_seq=18 ttl=64 time=0.054 ms64 bytes from combo73 (127.0.0.1): icmp_seq=19 ttl=64 time=0.058 ms64 bytes from combo73 (127.0.0.1): icmp_seq=20 ttl=64 time=0.064 ms64 bytes from combo73 (127.0.0.1): icmp_seq=21 ttl=64 time=0.104 ms^C--- combo73 ping statistics ---21 packets transmitted, 21 received, 0% packet loss, time 20030msrtt min/avg/max/mdev = 0.029/0.060/0.148/0.025 ms

hostnamectl set-hostname 新主机名

hostnamectl set-hostname combo73

[root@combo73 ~]# hostnamectlStatic hostname: combo73Icon name: computer-vmChassis: vmMachine ID: f5b4422ae39d4e5ab2e0fc32018cc6feBoot ID: f44ad9cf36b84812b4ab0956d1a3216dVirtualization: vmwareOperating System: CentOS Linux 7 (Core)CPE OS Name: cpe:/o:centos:centos:7Kernel: Linux 3.10.0-1160.90.1.el7.x86_64Architecture: x86-64

修改主机名后，可以看到临时主机名消失了

重新登录下，环境变量中的主机名和命令提示符中的主机名也改过来了

[root@combo73 ~]# echo $HOSTNAME

combo73

改下/etc/hosts中的配置

修改前：

127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4::1 localhost localhost.localdomain localhost6 localhost6.localdomain6

修改为：

127.0.0.1 combo73127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4::1 combo73::1 localhost localhost.localdomain localhost6 localhost6.localdomain6