Sorry for the lapse in posting. I am working on something that I think is pretty cool. Should be ready for publication soon!
But back to IOS XR for a quick post!
A really cool thing with IOS XR is interface wildcards.
If you want to only see the Loopback interfaces, all of them. Normally you would do something like Show int br | in Loop, but with XR you can use a wildcard (*)
RP/0/7/CPU0:R1#sh int l* br
Mon Apr 16 17:21:08.088 UTC
Intf Intf LineP Encap MTU BW
Name State State Type (byte) (Kbps)
———————————————————————-
Lo0 up up Loopback 1500 0
Lo100 up up Loopback 1500 0
Lo666 up up Loopback 1500 0
Lo667 up up Loopback 1500 0
Lo1000 up up Loopback 1500 0
RP/0/7/CPU0:R1#

This works the same if you want to see this in the running config:
RP/0/7/CPU0:R1#sh run in l*
Mon Apr 16 17:21:53.360 UTC
interface Loopback0
ipv4 address 1.1.1.1 255.255.255.255
ipv6 address 2001::1/128
!
interface Loopback100
ipv4 address 100.100.100.100 255.255.255.255
!
interface Loopback666
ipv4 address 6.6.6.6 255.255.255.255
!
interface Loopback667
ipv4 address 6.6.6.7 255.255.255.255
!
interface Loopback1000
vrf LAB
ipv4 address 111.111.111.111 255.255.255.255
!
RP/0/7/CPU0:R1#
 
Told ya it was going to be a quick on!