Command Processing


Command handler provides a common command line interface (CLI). Command line must be text. Commands should be separated with a single character. CLI can be used with:

  • Serial

  • Network (Websockets, Telnet)

and all communication protocols that are exchanging text data.

Commands can be added to and removed from the command handler. Each command will trigger a defined Delegate.

A welcome message may be shown when a user connects and end-of-line (EOL) character may be defined. An automatic “help” display is available.

For more examples take a look at the CommandLine, TelnetServer and HttpServer Websockets samples.


  1. Add these lines to your application file:

    COMPONENT_DEPENDS += CommandProcessing
  2. Add these lines to your application:

    #include <CommandProcessing/Utils.h>
  3. Basic example:

    #include <CommandProcessing/Utils.h>
    CommandProcessing::Handler commandHandler;
    void processShutdownCommand(String commandLine, ReadWriteStream& commandOutput)
      // ...
    void init()
      commandHandler.registerCommand({CMDP_STRINGS("shutdown", "Shutdown Server Command", "Application"), processShutdownCommand});

default: undefined (RAM strings) 1: Store strings in flash memory

Command name, help and group strings default to RAM. This maintains backward compatibility with existing applications which may define commands like this:

commandHandler.registerCommand({"shutdown", "Shutdown Server Command", "Application", processShutdownCommand});

To save RAM, update your code to use the CMDP_STRINGS macro and build with CMDPROC_FLASHSTRINGS=1.

API Documentation

CMDP_STRINGS(name, help, group)


Used by

Environment Variables

SoC support

  • esp32

  • esp32c2

  • esp32c3

  • esp32s2

  • esp32s3

  • esp8266

  • host

  • rp2040