ip alias

1. show ip alias

It will should all the IP address, it is better than using show ip int bri.

2. ip alias can be use for un-exist host.
Sample configuration:
R1#(config)int fa 1/0
R1#(config-inf) ip add 192.168.1.2 255.255.255.0
R1#(config)ip alias 192.168.1.10 23

when you ping 192.168.1.10, the arp will resolve from 192.168.1.2. When you telnet 192.168.1.10, it will actually telnet to 192.168.1.2.

Usually, it will be used in reverse telnet.
ip alias 172.16.1.10 2001
ip alias 172.16.1.11 2002

So you can just "telnet 172.16.1.10" than it will reverse telnet to one of the serial ports.