$ ./go.sh addr
mode=addr DHCP_ADDR=172.31.31.71/20 ADDR=172.31.31.71/20 IFACE=eth0
exroute=169.254.169.254/32 dev eth0
$ ifdown eth0
Killed old client process
Internet Systems Consortium DHCP Client 4.3.3
Copyright 2004-2015 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/eth0/06:85:a8:ac:84:b5
Sending on   LPF/eth0/06:85:a8:ac:84:b5
Sending on   Socket/fallback
DHCPRELEASE on eth0 to 172.31.16.1 port 67 (xid=0x47230f30)
$ ip addr add 172.31.31.71/20 dev eth0
$ ip link set dev eth0 up
$ ip route add 169.254.169.254/32 dev eth0
$ wget http://169.254.169.254/ --timeout=2 -O - --tries=2
--2017-07-10 18:09:30--  http://169.254.169.254/
Connecting to 169.254.169.254:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 197 [text/plain]
Saving to: ‘STDOUT’
1.0
2007-01-19
2007-03-01
2007-08-29
2007-10-10
2007-12-15
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2016-09-02
latest
     0K                                                       100% 27.3M=0s

2017-07-10 18:09:30 (27.3 MB/s) - written to stdout [197/197]

$ ip route del 169.254.169.254/32 dev eth0
$ ip addr flush dev eth0
$ ip link set dev eth0 down
$ ifup eth0
Internet Systems Consortium DHCP Client 4.3.3
Copyright 2004-2015 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/eth0/06:85:a8:ac:84:b5
Sending on   LPF/eth0/06:85:a8:ac:84:b5
Sending on   Socket/fallback
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3 (xid=0x2ee3aa4f)
DHCPREQUEST of 172.31.31.71 on eth0 to 255.255.255.255 port 67 (xid=0x4faae32e)
DHCPOFFER of 172.31.31.71 from 172.31.16.1
DHCPACK of 172.31.31.71 from 172.31.16.1
bound to 172.31.31.71 -- renewal in 1528 seconds.