get all keys
keys *
Keys starting with my query keys my?
delete key del my1
Batch deletion is del key1 key2 key3
Check whether a certain key exists, 1 exists, 0 does not exist
exists my1
Rename the key: rename num1 mynum
rename num1 to mynum
expire mynum 1000 (expired and deleted after 1000 seconds)
ttl mynum View the remaining time of mynum
Returns -1 if not set
Get the type of the specified key
type xxx
(yuwen was emptied by me, so he was also deleted and returned to None)