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redis-cli

redis-cli, the Redis command line interface

redis-cli is the Redis command line interface, a simple program that allows to send commands to Redis, and read the replies sent by the server, directly from the terminal.

It has two main modes: an interactive mode where there is a REPL (Read Eval Print Loop) where the user types commands and get replies; and another mode where the command is sent as arguments of redis-cli, executed, and printed on the standard output.

NOTE: 第二个mode所指的是如下这种使用方式： 

redis-cli KEYS "prefix:*" | xargs redis-cli DEL

In interactive mode, redis-cli has basic line editing capabilities to provide a good typing experience.

However redis-cli is not just that. There are options you can use to launch the program in order to put it into special modes, so that redis-cli can definitely do more complex tasks, like simulate a slave and print the replication stream it receives from the master, check the latency of a Redis server and show statistics or even an ASCII-art spectrogram of latency samples and frequencies, and many other things.

This guide will cover the different aspects of redis-cli, starting from the simplest and ending with the more advanced ones.

SUMMARY : redis-cli不仅仅只有上述的mode，还有其他的mode，参见Special modes of operation

If you are going to use Redis extensively, or if you already do, chances are you happen to use redis-cli a lot. Spending some time to familiarize with it is likely a very good idea, you'll see that you'll work more effectively with Redis once you know all the tricks of its command line interface.

Command line usage

Host, port, password and database

Getting input from other programs

Continuously run the same command

Mass insertion of data using redis-cli

CSV output

Running Lua scripts

Interactive mode

Handling connections and reconnections

Editing, history and completion

Running the same command N times

Showing help about Redis commands

Special modes of operation

So far we saw two main modes of redis-cli.

  • Command line execution of Redis commands.
  • Interactive "REPL-like" usage.

However the CLI performs other auxiliary tasks related to Redis that are explained in the next sections:

  • Monitoring tool to show continuous stats about a Redis server.
  • Scanning a Redis database for very large keys.
  • Key space scanner with pattern matching.
  • Acting as a Pub/Sub client to subscribe to channels.
  • Monitoring the commands executed into a Redis instance.
  • Checking the latency of a Redis server in different ways.
  • Checking the scheduler latency of the local computer.
  • Transferring RDB backups from a remote Redis server locally.
  • Acting as a Redis slave for showing what a slave receives.
  • Simulating LRU workloads for showing stats about keys hits.
  • A client for the Lua debugger.

实现分析

“interactive mode ”的入口函数是：repl

"Command line execution of Redis commands"的 "Running Lua scripts"的入口函数是:evalMode

redis所支持的所有的command都在"help.h"中定义.

如何组织所有的command？

如何组织所有的command和command对应的执行函数？