This example illustrates the usage of the [Console Component](https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/console.html#console) to create an interactive shell on the ESP32. The interactive shell running on the ESP32 can then be controlled/interacted with over a serial port (UART).
The interactive shell implemented in this example contains a wide variety of commands, and can act as a basis for applications that require a command-line interface (CLI).
Enter the `help` command get a full list of all available commands. The following is a sample session of the Console Example where a variety of commands provided by the Console Example are used. Note that GPIO15 is connected to GND to remove the boot log output.
The line endings in the Console Example are configured to match particular serial monitors. Therefore, if the following log output appears, consider using a different serial monitor (e.g. Putty for Windows) or modify the example's [UART configuration](#Configuring-UART-and-VFS).
```
This is an example of ESP-IDF console component.
Type 'help' to get the list of commands.
Use UP/DOWN arrows to navigate through command history.
Press TAB when typing command name to auto-complete.
Your terminal application does not support escape sequences.
Line editing and history features are disabled.
On Windows, try using Putty instead.
esp32>
```
## Example Breakdown
### Configuring UART
The ``initialize_console()`` function in the example configures some aspects of UART relevant to the operation of the console.
- **Line Endings**: The default line endings are configured to match those expected/generated by common serial monitor programs, such as `screen`, `minicom`, and the `idf_monitor.py` included in the SDK. The default behavior for these commands are:
- When 'enter' key is pressed on the keyboard, `CR` (0x13) code is sent to the serial device.
- To move the cursor to the beginning of the next line, serial device needs to send `CR LF` (0x13 0x10) sequence.
### Line editing
The main source file of the example illustrates how to use `linenoise` library, including line completion, hints, and history.
### Commands
Several commands are registered using `esp_console_cmd_register()` function. See the `register_wifi()` and `register_system()` functions in `cmd_wifi.c` and `cmd_system.c` files.
### Command handling
Main loop inside `app_main()` function illustrates how to use `linenoise` and `esp_console_run()` to implement read/eval loop.
### Argument parsing
Several commands implemented in `cmd_wifi.c` and `cmd_system.c` use the Argtable3 library to parse and check the arguments.
Each time a new command line is obtained from `linenoise`, it is written into history and the history is saved into a file in flash memory. On reset, history is initialized from that file.
