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本文主要介绍在RHEL/CentOS/6/7/8中如何修改主机的hostname。

1、CentOS6/RHEL6

对于6系的红帽Linux，修改hostname较为麻烦，如果只是需要临时修改hostname，只需要使用hostname命令即可：

hostname your-new-temp-hostname

如果需要永久修改hostname，则需要修改两个地方：

首先是/etc/hosts文件中，需要添加IP和hostname的映射关系，如：

127.0.0.1   your-new-perm-hostname

然后在/etc/sysconfig/network文件中修改对应的HOSTNAME=参数为新的hostname

HOSTNAME=your-new-perm-hostname

注意两处地方需要同时修改，否则会报错，最后需要重启系统才会生效。

2、CentOS7、8/RHEL7、8

对于7系及之后的红帽Linux，只需要直接修改/etc/hostname文件然后重启就可以完成永久修改

如果不想重启，可以使用新的hostnamectl工具来进行永久修改

hostnamectl set-hostname your-new-perm-hostname

3、使用脚本自动执行

#!/bin/bash
# Determine  whether executor is root or not
if [ $(whoami) != "root" ]; then
    echo "please exec this shell script with sudo or in root mode"
    exit 1
fi

# Determine if there is a new hostname
if [ -z "$1" ]; then
    echo "please input the new hostname"
    exit 1
fi

# get the release version
version=$(cat /etc/redhat-release | awk -F 'release' '{print $2}' | cut -c -2)

if [ $version -ne 6 ] && [ $version -ne 7 ] && [ $version -ne 8 ]; then
    echo "This script do not suit your system, Bye!"
    exit 1
fi

echo "your hostname will be change to $1"

if [ $version == 6 ]; then
    # get hostname from /etc/sysconfig/network
    hostnameCurrent=$(cat /etc/sysconfig/network | grep HOSTNAME | awk -F '=' '{ print $NF }')
    # echo "your hostname now is $hostnameCurrent"
    # modify the tmp hostname
    hostname $1
    # Determine if there is a field about $hostnameCurrent in /etc/hosts
    # if yes, use awk to replace it
    # if no, echo a new line aboout new hostname
    cat /etc/hosts | grep $hostnameCurrent
    if [ $? -ne 0 ]; then
        echo "127.0.0.1     $1" >>/etc/hosts
    else
        sed -i "s/$hostnameCurrent/$1/g" /etc/hosts
    fi
    # modify the hostname in /etc/sysconfig/network
    sed -i "s/$hostnameCurrent/$1/g" /etc/sysconfig/network
else
    if [ $version == 7 ] || [ $version == 8 ]; then
        hostnamectl set-hostname $1
    fi
fi

echo "Hostname modification is done !"
echo "A restart might be better for apply the change"

将上述的代码保存为脚本再加上需要修改的hostname直接执行就可以了。