keys */查看所有的key
remoteSelf:1>select 0
"OK"
remoteSelf:0>keys *
1) "SUBCRIBEMAP"
2) "test"
exists key名字/判断某个key是否存在
# 不存在返回0
remoteSelf:0>exists aaa
"0"
# 存在返回1
remoteSelf:0>exists test
"1"
remoteSelf:1>select 0
"OK"
remoteSelf:0>keys *
1) "SUBCRIBEMAP"
2) "test"
# 不存在返回0
remoteSelf:0>exists aaa
"0"
# 存在返回1
remoteSelf:0>exists test
"1"