$ ./extract-ip.rb s1-pinglogs-2016-10-19_17-25-51/
192.168.11.146    ec:f4:bb:41:00:a1
192.168.11.160    ec:f4:bb:41:01:fc
192.168.11.72     4c:cc:6a:58:c4:01
192.168.11.156    ec:f4:bb:41:00:a1
192.168.11.229    ec:f4:bb:41:00:44
192.168.11.202    ec:f4:bb:41:00:e5
192.168.11.164    54:ee:75:54:a3:1f
192.168.11.193    ec:f4:bb:41:01:6c
192.168.11.138    ec:f4:bb:41:01:5e
192.168.11.217    ec:f4:bb:41:00:e9
192.168.11.161    08:00:27:27:06:d4
192.168.11.252    ec:f4:bb:41:00:82
192.168.11.185    ec:f4:bb:41:00:b1
192.168.11.1      00:1b:21:48:23:ce
192.168.11.170    3c:97:0e:e5:db:83
192.168.11.144    ec:f4:bb:41:01:2c
192.168.11.130    3c:97:0e:e5:db:61
192.168.11.73     4c:cc:6a:58:c4:08
192.168.11.71     4c:cc:6a:58:c4:19
192.168.11.241    3c:97:0e:99:b6:ed
192.168.11.132    ec:f4:bb:41:00:ee
192.168.11.247    54:ee:75:54:a4:b4
192.168.11.70     90:2b:34:11:24:92
192.168.11.60     3c:97:0e:99:b7:e2
192.168.11.74     4c:cc:6a:58:c4:05
192.168.11.68     34:40:b5:db:10:f8
192.168.11.162    3c:97:0e:99:b4:fe