$ cat ifconfig.txt
eth0      Link encap:Ethernet HWaddr 08:00:27:E2:70:A4
          inet addr:10.0.2.5 Bcast:10.0.2.255 Mask:255.255.255.0  ← アドレスが設定されている
          inet6 addr: fe80::a00:27ff:fee2:70a4/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
          RX packets:11 errors:0 dropped:0 overruns:0 frame:0
          TX packets:15 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:995 (995.0 b) TX bytes:1156 (1.1 KiB)
          Interrupt:11 Base address:0xc020

lo        Link encap:Local Loopback
          inet addr:127.0.0.1 Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING MTU:16436 Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)