linux-获取动态IP,然后获取Grep和Echo Hosts文件

我有一个dns&我们公司的apachi服务器,它的IP地址是动态的
我已经尝试执行以下操作：

#!/bin/bash
# Get the dynamic IP (dirty, I kNow)
IP=`host -t a mychangingip.myip.com | perl -nle '/((?:\d+\.?){4})/ && print $1' | head -n1`
# Update the hosts file
if test -n "$IP"; then
    grep -v www.thesite.com /etc/hosts > /tmp/hosts
    echo "$IP www.thesite.com" >> /tmp/hosts
    cp /tmp/hosts /etc/hosts
fi

到目前为止,此步骤工作正常,但是当我尝试执行以下操作时：

#!/bin/bash
# Get the dynamic IP (dirty, I kNow)
IP=`host -t a mychangingip.myip.com | perl -nle '/((?:\d+\.?){4})/ && print $1' | head -n1`
# Update the hosts file
if test -n "$IP"; then
    grep -v www.thesite.com /etc/hosts > /tmp/hosts
    grep -v portal.thesite.com /etc/hosts > /tmp/hosts
    echo "$IP www.thesite.com" >> /tmp/hosts/
    echo "$IP portal.thesite.com" >> /tmp/hosts
    cp /tmp/hosts /etc/hosts
fi

它无法正常工作,只能更新一项

解决方法:

更换：

grep -v www.thesite.com /etc/hosts > /tmp/hosts
grep -v portal.thesite.com /etc/hosts > /tmp/hosts

与：

grep -v www.thesite.com /etc/hosts > /tmp/hosts2
grep -v portal.thesite.com /etc/hosts2 > /tmp/hosts

或者,将两行都替换为：

grep -v 'www.thesite.com\|portal.thesite.com' /etc/hosts > /tmp/hosts

进一步简化

考虑替换以下五行：

grep -v www.thesite.com /etc/hosts > /tmp/hosts
grep -v portal.thesite.com /etc/hosts > /tmp/hosts
echo "$IP www.thesite.com" >> /tmp/hosts/
echo "$IP portal.thesite.com" >> /tmp/hosts
cp /tmp/hosts /etc/hosts

通过这一行：

sed -i.bak "/www.thesite.com|portal.thesite.com/ s/[^[[:space:]]*/$IP/" /etc/hosts