-> show interfaces terse | match xe-4/0/0
-> show configuration | match xe-4/0/0 | display set | display inheritance
or you need to know remote IP:
-> show arp interface ge-1/1/0.0
re0> show interfaces terse | match xe-4/0/0
xe-4/0/0 up down
xe-4/0/0.0 up down inet 192.168.2.1 --> 0/0
re0> show configuration | match xe-4/0/0 | display set | display inheritance
set interfaces xe-4/0/0 unit 0 family inet address 192.168.2.1/32
re0# run show arp interface ge-1/1/0.0
MAC Address Address Name Interface Flags
64:87:88:5e:f3:50 50.1.1.2 50-1-1-2.dsl.dynamic.fusi ge-1/1/0.0 none