dhclient -r #用于释放ip地址
2 dhclient #获取IP地址
主要针对只有命令行的Linux机器,临时改变了网络环境，事先手动设置的ip地址
看一下自带的解释
root@ubuntu:~# whatis dhclient
dhclient () - Dynamic Host Configuration Protocol Client
下面是help
root@ubuntu:~# dhclient --help
Internet Systems Consortium DHCP Client 4.3.
Copyright - Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Unknown command: --help
Usage: dhclient [-|-] [-SNTPRI1dvrxi] [-nw] [-p <port>] [-D LL|LLT]
[-s server-addr] [-cf config-file]
[-df duid-file] [-lf lease-file]
[-pf pid-file] [--no-pid] [-e VAR=val]
[-sf script-file] [interface]*