Finding Serial Number in Cisco IOS-XR (ASR9K)

Why this has to be so complicated I’ll never know, but these seem to work:

Method 1:

RP/0/RSP0/CPU0:router#
RP/0/RSP0/CPU0:router#admin

RP/0/RSP0/CPU0:router(admin)#show dsc
---------------------------------------------------------
           Node  (     Seq)     Role       Serial State
---------------------------------------------------------
    0/RSP0/CPU0  (       0)   ACTIVE  ABC12345678 PRIMARY-DSC

RP/0/RSP0/CPU0:router(admin)#exit
RP/0/RSP0/CPU0:router#

Method 2:

RP/0/RSP0/CPU0:router#
RP/0/RSP0/CPU0:router#admin

RP/0/RSP0/CPU0:router(admin)#show diag chassis

Rack 0 - ASR 9006 4 Line Card Slot Chassis with V2 AC PEM
  RACK NUM: 0
  S/N:   ABC12345678
  PID:   ASR-9006-AC-V2
  VID:   V02
  Desc:  ASR 9006 4 Line Card Slot Chassis with V2 AC PEM
  CLEI:  IPMUP00BRB
  Top Assy. Number:   12-3456-78

RP/0/RSP0/CPU0:router(admin)#exit
RP/0/RSP0/CPU0:router#

Method 3:

RP/0/RSP0/CPU0:router#
RP/0/RSP0/CPU0:router#admin

RP/0/RSP0/CPU0:router(admin)#show inventory rack

  Rack                 Chassis PID           S/N
  ----                 ------------      ----------
  0                    ASR-9006-AC-V2       ABC12345678

RP/0/RSP0/CPU0:router(admin)#exit
RP/0/RSP0/CPU0:router#

Method 4:

You tell me 😉