ifconfig is the equivalent of ipconfig in DOS where you can configure network interface.
Without parameters, it gives you the list of interface with their corresponding IP.
apt-get install -y net-tools
Below you can see two interfaces :
[root@oel11g ~]# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0C:29:79:3E:8C
inet addr:192.168.96.232 Bcast:192.168.97.255 Mask:255.255.254.0
inet6 addr: fe80::20c:29ff:fe79:3e8c/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:71800 errors:0 dropped:0 overruns:0 frame:0
TX packets:9218 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:16185577 (15.4 MiB) TX bytes:1167946 (1.1 MiB)
Interrupt:59 Base address:0x2000
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:4770 errors:0 dropped:0 overruns:0 frame:0
TX packets:4770 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:6175911 (5.8 MiB) TX bytes:6175911 (5.8 MiB)