#!/bin/bashPATH=/sbin:/usr/sbin:/usr/local/sbin:/root/bin:/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/X11R6/bin:/usr/games:/opt/kde3/bin:/usr/lib/mit/bin:/usr/lib/mit/sbinexport PATHNew_Hostname=$1OSRelease=`lsb_release -i|awk -F : ‘{print $2}‘|sed ‘s/\t//g‘`#1 Modify /etc/hosts or add one loop entryOld_Hostname=`grep ${HOSTNAME} /etc/hosts|wc -l`if [ "$Old_Hostname" != "0"x ]; then    sed -i "s/${HOSTNAME}/${New_Hostname}/g" /etc/hostselse    echo "127.0.0.10 ${New_Hostname}">>/etc/hostsfi#2 Modify different OS‘s hostname if [[ ${OSRelease} =~ ‘SUSE‘ ]]; then    echo "this is SUSE machine";    #modify /etc/HOSTNAME file    echo ${New_Hostname}>/etc/HOSTNAME;    #immediate effect    /etc/rc.d/boot.localnet stop;    /etc/rc.d/boot.localnet start;elif [[ ${OSRelease} =~ ‘RedHat‘ ]]; then    echo "this is RedHat machine";    sed -i "s/${HOSTNAME}/${New_Hostname}/g" /etc/sysconfig/network;    else     echo "this is donnotknow";fi#3 Modify variblehostname ${New_Hostname}export HOSTNAME=${New_Hostname}echo "Hostname modify successfull!"#今天在写一个脚本遇到问题，----需要在sed中引入shell变量，在网上搜了变天才找到，经过测试##这四种方法都可用，在这里跟大家分享下，=---同时谢谢netman大哥，前辈就是前辈哈哈##1.eval sed ’s/$a/$b/’ filename#2.sed "s/$a/$b/" filename#3.sed ’s/’$a’/’$b’/’ filename#4.sed s/$a/$b/ filename