从Redis列表中删除除后5个值以外的10个值
redis 127.0.0.1:6379> rpush foo 1
(integer) 1
redis 127.0.0.1:6379> rpush foo 2
(integer) 2
redis 127.0.0.1:6379> rpush foo 3
(integer) 3
redis 127.0.0.1:6379> rpush foo 4
(integer) 4
redis 127.0.0.1:6379> rpush foo 5
(integer) 5
redis 127.0.0.1:6379> rpush foo 6
(integer) 6
redis 127.0.0.1:6379> rpush foo 7
(integer) 7
redis 127.0.0.1:6379> rpush foo 8
(integer) 8
redis 127.0.0.1:6379> rpush foo 9
(integer) 9
redis 127.0.0.1:6379> rpush foo 10
(integer) 10
redis 127.0.0.1:6379> lrange foo 0 -1
1) "1"
2) "2"
3) "3"
4) "4"
5) "5"
6) "6"
7) "7"
8) "8"
9) "9"
10) "10"
redis 127.0.0.1:6379> ltrim foo -5 -1
OK
redis 127.0.0.1:6379> lrange foo 0 -1
1) "6"
2) "7"
3) "8"
4) "9"
5) "10"
redis 127.0.0.1:6379>
简化后为:ltrim {キー名} -{保留数量} -1。