SET

127.0.0.1:6379> set user_id 42
OK

GET

127.0.0.1:6379> get user_id
42

#Retrieve all keys
127.0.0.1:6379> keys *
item3
item2
item1

SET (Update)

127.0.0.1:6379> set user_id 99
OK
127.0.0.1:6379> get user_id
99

DEL

127.0.0.1:6379> del user_id
1
127.0.0.1:6379> get user_id
(nil)

EXISTS

127.0.0.1:6379> EXISTS username
0
127.0.0.1:6379> SET username admin
OK
127.0.0.1:6379> EXISTS username
1

TTL

127.0.0.1:6379> TTL username
-1		#No expiration

127.0.0.1:6379> TTL username
3		#Expires in 3 seconds

127.0.0.1:6379> TTL username
-2		#Key has expired

Setting Expiration: PX / EX

#Set expiration in milliseconds
127.0.0.1:6379> set username john px 10000
OK

#Set expiration in seconds
127.0.0.1:6379> set password secret ex 10
OK

SETEX (Combine SET and EX)

127.0.0.1:6379> SETEX username 10 john
OK

PSETEX (Combine SET and PX)

127.0.0.1:6379> PSETEX username 1000 john
OK

NX - Set Only If Key Does Not Exist

127.0.0.1:6379> set counter 100
OK
127.0.0.1:6379> set counter 200 nx		#Key counter exists, value unchanged
(nil)
127.0.0.1:6379> get counter
100

127.0.0.1:6379> set new_counter 300 nx		#Key new_counter does not exist, creates it
OK
127.0.0.1:6379> get new_counter
300

SETNX

127.0.0.1:6379> SETNX counter 999
0
127.0.0.1:6379> get counter
100
127.0.0.1:6379> SETNX total 500
1
127.0.0.1:6379> get total
500

XX - Set Only If Key Exists

127.0.0.1:6379> get counter
100
127.0.0.1:6379> set counter 888 xx
OK
127.0.0.1:6379> get counter
888
127.0.0.1:6379> set missing_key 999 xx
(nil)
127.0.0.1:6379> get missing_key
(nil)

MSET - Set Multiple Values

127.0.0.1:6379> MSET product_id 25 price 49.99 quantity 100
OK
127.0.0.1:6379> keys *
product_id
price
quantity
127.0.0.1:6379> get product_id
25
127.0.0.1:6379> get price
49.99
127.0.0.1:6379> get quantity
100

GETSET

127.0.0.1:6379> get product_id
25
127.0.0.1:6379> getset product_id 30
25
127.0.0.1:6379> get product_id
30

SETRANGE - Update by Endex

127.0.0.1:6379> set code abcdefg
OK
127.0.0.1:6379> get code
abcdefg
127.0.0.1:6379> SETRANGE code 3 XX
7
127.0.0.1:6379> get code
abcXXfg

MGET - Get Multiple Values

127.0.0.1:6379> get code
abcXXfg
127.0.0.1:6379> get price
49.99
127.0.0.1:6379> MGET code price
abcXXfg
49.99

GETRANGE - Substring

127.0.0.1:6379> get code
abcdefg
127.0.0.1:6379> GETRANGE code 2 -1		#Get all from index 2
cdefg
127.0.0.1:6379> GETRANGE code 2 2		#Get single character at index 2
c
127.0.0.1:6379> GETRANGE code 2 4		#Get range from index 2 to 4
cde

INCR - Increment

127.0.0.1:6379> set views 1
OK
127.0.0.1:6379> INCR views
2
127.0.0.1:6379> INCR views
3
127.0.0.1:6379> INCR views
4
127.0.0.1:6379> INCR views
5

DECR - Decrement

127.0.0.1:6379> get views
5
127.0.0.1:6379> DECR views
4
127.0.0.1:6379> DECR views
3
127.0.0.1:6379> DECR views
2
127.0.0.1:6379> DECR views
1

INCRBY - Increment by Step

127.0.0.1:6379> get balance
10
127.0.0.1:6379> INCRBY balance 50
60
127.0.0.1:6379> INCRBY balance 50
110
127.0.0.1:6379> INCRBY balance 50
160
127.0.0.1:6379> INCRBY balance 50
210
127.0.0.1:6379> INCRBY balance 50
260

DECRBY - Decrement by Step

127.0.0.1:6379> get balance
260
127.0.0.1:6379> DECRBY balance 30
230
127.0.0.1:6379> DECRBY balance 30
200
127.0.0.1:6379> DECRBY balance 30
170
127.0.0.1:6379> DECRBY balance 30
140

APPEND

127.0.0.1:6379> get message
hi
127.0.0.1:6379> APPEND message world
8
127.0.0.1:6379> get message
hiworld