Discerning the IP (deprecated method)

On older systems, or those managed by stick-in-the-mud admins, you might also use ifconfig to find the IP and subnet.

Simply running ifconfig will print all relevant information:

$ ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
 inet 10.0.2.15 netmask 255.255.255.0 broadcast 10.0.2.255
 inet6 fe80::5054:ff:fec9:c704 prefixlen 64 scopeid 0x20<link>
 ether 52:54:00:c9:c7:04 txqueuelen 1000 (Ethernet)
 RX packets 14404 bytes 12885029 (12.2 MiB)
 RX errors 0 dropped 0 overruns 0 frame 0
 TX packets 5672 bytes 409079 (399.4 KiB)
 TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
 inet 192.168.33.10 netmask 255.255.255.0 broadcast 192.168.33.255
 inet6 fe80::a00:27ff:fe4b:3de prefixlen 64 scopeid 0x20<link>
 ether 08:00:27:4b:03:de txqueuelen 1000 (Ethernet)
 RX packets 8 bytes 3164 (3.0 KiB)
 RX errors 0 dropped 0 overruns 0 frame 0
 TX packets 17 bytes 1906 (1.8 KiB)
 TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

eth2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
 ether 08:00:27:50:a5:cb txqueuelen 1000 (Ethernet)
 RX packets 43 bytes 14706 (14.3 KiB)
 RX errors 0 dropped 0 overruns 0 frame 0
 TX packets 112 bytes 19336 (18.8 KiB)
 TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
 inet 127.0.0.1 netmask 255.0.0.0
 inet6 ::1 prefixlen 128 scopeid 0x10<host>
 loop txqueuelen 1000 (Local Loopback)
 RX packets 0 bytes 0 (0.0 B)
 RX errors 0 dropped 0 overruns 0 frame 0
 TX packets 0 bytes 0 (0.0 B)
 TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

As with IP, it's trivial to dump the information about a specific interface.

As we can see in the following code, we're looking again at the specifics of eth1:

$ ifconfig eth1
eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.33.10  netmask 255.255.255.0  broadcast 192.168.33.255
        inet6 fe80::a00:27ff:fe0d:d90c  prefixlen 64  scopeid 0x20<link>
        ether 08:00:27:0d:d9:0c  txqueuelen 1000  (Ethernet)
        RX packets 24  bytes 4268 (4.1 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 20  bytes 2116 (2.0 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0