If you want to list the last shutdown’s of a server just type:
# last -x shutdown
shutdown system down 3.16.0-4-amd64 Sun Dec 20 22:14 - 08:28 (10:14)
shutdown system down 3.16.0-4-amd64 Sat Dec 19 15:26 - 10:41 (19:15)
shutdown system down 3.16.0-4-amd64 Sat Dec 19 14:35 - 15:24 (00:48)
shutdown system down 3.16.0-4-amd64 Fri Dec 18 18:04 - 09:46 (15:42)
shutdown system down 3.16.0-4-amd64 Fri Dec 18 10:01 - 15:46 (05:44)
