Guides on Using the Commands in Redis Cheat Sheet Part 1

Introduction

This is part one of a Redis cheat sheet tutorial series. Redis, an acronym for Remote Directory Server, is an in-memory database that supports multiple data types. Redis works by mapping keys to values that functions as a key-value-based caching system. Redis commands perform some operations on Redis server, with some commands being able to be executed from the Redis command-line interface, or CLI. The CLI is an uncomplicated program that permits the sending of commands to and reading the replies from Redis directly from the terminal. This fist section of this tutorial series will provide instructions for using many of the Redis commands.

Prerequisites

• A properly running Redis server and Redis CLI installed and working on the local device are required to follow the examples provided in this Redis cheat sheet tutorial.

• Execute of the redis-cli PING command will return an output of PONG if Redis is installed. The sudo systemctl status redis command in a Linux distribution system will also verify if Redis is running.

Display the information on the Redis cli server statics

Execute the following INFO command to obtain the statistics of the Redis server in a readable format:

The results should provide information similar to the following on the parameters that a computer is able to parse:

• server: Information about the Redis server on the local device, such as the version number and pertinent data.

• clients: The section where the clients connections are counted.

• memory: Provides information on memory usage of the server and other related data.

• persistence: Gives information about the Redis database backup and the Append Only file.

• stats: Provides general information regarding the statistics in Redis.

• replication: Supplies role master and replication data.

• cpu: Information about CPU consumption.

• cluster: This shows the cluster section of the Redis server.

• keyspace: Relates to database statistics.

Accessing the interactive cli tool for Redis

Execute the redis-cli command in the terminal to open the prompt that accesses the Redis command-line interface tool.

• Execute the following command to monitor the currently active commands in Redis:

NOTE: Executing the CTRL + C will end the above operation.

• The following command will display the maximum number of the databases in Redis:

• The following command will list all available databases:

• Now execute the following command to select the desired database:

This will present an index of databases, displayed as numbers. For example, the default database in Redis is [0], so executing this command allows for switching to another database. The output should resemble the following:

Now the second database, which has the index of [1], can be selected.

• Execute the following command to drop the currently selected database:

Note that changing the DB to ALL after the FLUSH command will drop all of the databases.

String commands in Redis

The basic type of value in Redis is known as a string and may contain any type of the data.

The APPEND function

• This shows how to append the key value:

BITCOUNT function

• This counts the set bits number.

The DECR function

• This will decrement the integer by one:

The DECRBY function

• This function decrements the integer value of given number:

The GET function

• This returns the value of the key:

The GETRANGE function

• This will return the substring value of the key:

The GETSET function

• This function will set the new value of the key and return the old value:

The INCR function

• This increments the value of the key:

The INCRBY function

• This function will increment the integer value of given number:

The INCRBYFLOAT function

• This will increment the given value of the key by a float value:

The MSET function

• This function sets a multiple key with a multiple-key value:

The MGET function

• This will return the value of all of the given keys:

The MSETNX function

• This function sets the multiple key value, but only if no value currently exists in the keys:

The SET function

• This sets the key value:

The SETBIT function

• This will offset the bit in the string value:

The SETNX function

• Like the MSETNX function, this will set the key value if no value currently exists:

The SETRANGE function

• This function will overwrite the stored string in the key starting with a specified offset:

The STRLEN function

• This returns the length of the key value:

Conclusion

This was part one in a Redis cheat sheet tutorial series that gave instructions for using many of the more common and basic Redis commands. Part one of of this series covered how to display the information on the Redis CLI server, how to access the interactive CLI tool for Redis and provided examples for over a dozen functions for Redis string commands. Remember that while the Redis CLI is a very useful tool for executing many Redis commands, it is not suitable for executing some of the more complicated Redis functions. Subsequent parts of this tutorial series will cover more of the commonly used Redis commands.