Here is one way to get the output:
RP/0/RP0/CPU0:ASR9912-B#admin show logging onboard uptime loc 0/2/CPU0
Sun Jun 4 13:03:01.509 UTC
-------------------------------------------------------------------------------
UPTIME CONTINUOUS INFORMATION (Node: node0_2_CPU0)
-------------------------------------------------------------------------------
Current reset reason : 0x05
Current uptime : 0 years 1 weeks 2 days 23 hours 0 minutes
-------------------------------------------------------------------------------
RP/0/RP0/CPU0:ASR9912-B#
Thanks,
Sam