方法：
sed -i "s:/etc/dhcp:/home:g" ztj.txt
#表示将ztj.txt文件中的/etc/dhcp目录替换成/home目录
[root@logstash ~]# cat ztj.txt
/etc/dhcp1
/etc/dhcp
/etc/dhcp2
/etc/dhcp3
/etc/dhcp4
[root@logstash ~]# sed -i "s:/etc/dhcp:/home:g" ztj.txt
[root@logstash ~]# cat ztj.txt
/home1
/home
/home2
/home3
/home4
[root@logstash ~]#
