1 dhclient -r #用於釋放ip地址
2 dhclient    #獲取IP地址

主要針對只有命令列的Linux機器,臨時改變了網路環境，事先手動設定的ip地址

看一下自帶的解釋

root@ubuntu:~# whatis dhclient
dhclient (8)         - Dynamic Host Configuration Protocol Client

下面是help

root@ubuntu:~# dhclient --help
Internet Systems Consortium DHCP Client 4.3.5
Copyright 
 
2004-2016 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Unknown command: --help
Usage: dhclient [-4|-6] [-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]*