First understand redis' data structure - string

Redis Five data types commonly used in ：
1、 character string （String）
2、 String list （List）
3、 Ordered string collection （Sorted list）
4、 Hash （Hash）
5、 String collection （Set）

One 、 Storage String Common commands
a. assignment set
b, Value get
c. Delete del
d. Increase or decrease in value incr/decr/incrby/decrby
e. The extension command append

[email protected] redis]# ./bin/redis-cli
127.0.0.1:6379> set girl Pretty
OK
127.0.0.1:6379> get girl
"Pretty"
127.0.0.1:6379> getset girl Lovely
"Pretty"
127.0.0.1:6379> get girl
"Lovely"
127.0.0.1:6379> set boy Hot
OK
127.0.0.1:6379> get boy
"Hot"
127.0.0.1:6379> del boy
(integer) 1
127.0.0.1:6379> get boy
(nil)
127.0.0.1:6379> incr num
(integer) 1
127.0.0.1:6379> get num
"1"
127.0.0.1:6379> incr num
(integer) 2
127.0.0.1:6379> get num
"2"
127.0.0.1:6379> decr num
(integer) 1
127.0.0.1:6379> get num
"1"
127.0.0.1:6379> decr num2
(integer) -1
127.0.0.1:6379> incrby num 5
(integer) 6
127.0.0.1:6379> decrby num 2
(integer) 4
127.0.0.1:6379> get num
"4"
127.0.0.1:6379>
127.0.0.1:6379>
127.0.0.1:6379> append num 4
(integer) 2
127.0.0.1:6379> get num
"44"
127.0.0.1:6379>