我在我们公司有一个dns＆apachi服务器，它的IP地址是dynamic的，我试图做到以下几点：
#!/bin/bash # Get the dynamic IP (dirty, I know) IP=`host -ta 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，这一步工作正常，但是当我尝试：
#!/bin/bash # Get the dynamic IP (dirty, I know) IP=`host -ta 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
它不能按预期工作，只更新一个条目
更换：
grep -v www.thesite.com /etc/hosts > /tmp/hosts grep -v portal.thesite.com /etc/hosts > /tmp/hosts
有：
grep -v www.thesite.com /etc/hosts > /tmp/hosts2 grep -v portal.thesite.com /etc/hosts2 > /tmp/hosts
或者，将两行替换为：
grep -v 'www.thesite.com\|portal.thesite.com' /etc/hosts > /tmp/hosts
考虑替换这五行：
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
有了这一行：
sed -i.bak "/www.thesite.com|portal.thesite.com/ s/[^[[:space:]]*/$IP/" /etc/hosts
供你参考：
grep -v 'www.thesite.com' /etc/hosts|grep -v 'portal.thesite.com' >/tmp/hosts echo -e $IP'\t\t'www.thesite.com >> /tmp/hosts echo -e $IP'\t\t'portal.thesite.com >> /tmp/hosts cat /tmp/hosts > /etc/hosts