The NodeMcu is an open-source development kit for the ESP8266 WiFi chip series which is compatible with Arduino software.

Install Drivers

In order to communicate with the microcontroller you'll need serial drivers. If you're running a Linux kernel 3 or up then they're already installed, just make sure your computer doesn't need a reboot since your last kernel update OR SOMETHING. Otherwise download and install Silicon Labs' CP210x USB to UART Bridge VCP Drivers.

Install arduino-cli

arduino-cli is a command line utility to manage boards and libraries and compile and flash code like the full-fledged Arduino IDE, but with your own favorite tools. Install it via your package manager where available, otherwise see the arduino-cli installation page.

$ sudo pamac install arduino-cli

Add the ESP8266 Repository to arduino-cli

arduino-cli doesn't maintain ESP8266 board packages in its default repository, but we can easily add a repository which does. Use the config init subcommand to generate a configuration file.

$ arduino-cli config init
Config file written: /home/lucidmachine/.arduino15/arduino-cli.yaml

Once the configuration file has been created, edit it to add an entry in the additional_urls list under board_manager.

# /home/lucidmachine/.arduino15/arduino-cli.yaml
board_manager:
  additional_urls:
    - http://arduino.esp8266.com/stable/package_esp8266com_index.json

Now update the index of cores. You should see that the ESP8266 index has been downloaded.

$ arduino-cli core update-index
Updating index: package_index.json downloaded
Updating index: package_index.json.sig downloaded
Updating index: package_esp8266com_index.json downloaded

Install ESP8266 Cores

Now that you can find them, install the ESP8266 cores.

$ arduino-cli core install esp8266:esp8266
Downloading packages...
esp8266:xtensa-lx106-elf-gcc@2.5.0-4-b40a506 already downloaded
esp8266:mkspiffs@2.5.0-4-b40a506 already downloaded
esp8266:mklittlefs@2.5.0-4-fe5bb56 already downloaded
esp8266:python3@3.7.2-post1 already downloaded
esp8266:esp8266@2.7.4 already downloaded
Installing esp8266:xtensa-lx106-elf-gcc@2.5.0-4-b40a506...
esp8266:xtensa-lx106-elf-gcc@2.5.0-4-b40a506 installed
Installing esp8266:mkspiffs@2.5.0-4-b40a506...
esp8266:mkspiffs@2.5.0-4-b40a506 installed
Installing esp8266:mklittlefs@2.5.0-4-fe5bb56...
esp8266:mklittlefs@2.5.0-4-fe5bb56 installed
Installing esp8266:python3@3.7.2-post1...
esp8266:python3@3.7.2-post1 installed
Installing esp8266:esp8266@2.7.4...
Configuring platform...
esp8266:esp8266@2.7.4 installed

Create a Test Project

Now create a new sketch with the sketch subcommand.

$ arduino-cli sketch new blink
Sketch created in: /home/lucidmachine/src/blink

And edit the generated file to contain some basic blink code, courtesy of the arduino-cli Getting Started guide.

// /home/lucidmachine/src/blink/blink.ino

void setup() {
    pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
    digitalWrite(LED_BUILTIN, HIGH);
    delay(1000);
    digitalWrite(LED_BUILTIN, LOW);
    delay(1000);
}

Compile and Upload the Test Sketch

To upload code to the board you'll need to first identify the board's Fully Qualified Board Name (FQBN) and the port to which it is attached. Plug your board in to your computer and run the board list subcommand.

$ arduino-cli board list
Port         Type              Board Name FQBN Core
/dev/ttyS0   Serial Port       Unknown
/dev/ttyUSB0 Serial Port (USB) Unknown

My board is attached to /dev/ttyUSB0.

If your board happens to be identified as "Unknown", then you'll need to pick the appropriate FQBN from the list of all boards. In my case I happen to know I've bought the NodeMcu with the ESP-12E Module, so I filter my search for 'nodemcu'.

$ arduino-cli board listall | grep -i 'nodemcu'
NodeMCU 0.9 (ESP-12 Module)     esp8266:esp8266:nodemcu
NodeMCU 1.0 (ESP-12E Module)    esp8266:esp8266:nodemcu2

esp8266:esp8266:nodemcu2 is my board's FQBN.

Now you can compile the sketch given your board's FQBN using the compile subcommand.

$ arduino-cli compile --fqbn esp8266:esp8266:nodemcuv2 blink
Executable segment sizes:
IROM   : 228624          - code in flash         (default or ICACHE_FLASH_ATTR)
IRAM   : 26752   / 32768 - code in IRAM          (ICACHE_RAM_ATTR, ISRs...)
DATA   : 1248  )         - initialized variables (global, static) in RAM/HEAP
RODATA : 688   ) / 81920 - constants             (global, static) in RAM/HEAP
BSS    : 24880 )         - zeroed variables      (global, static) in RAM/HEAP
Sketch uses 257312 bytes (24%) of program storage space. Maximum is 1044464 bytes.
Global variables use 26816 bytes (32%) of dynamic memory, leaving 55104 bytes for local variables.
Maximum is 81920 bytes.

If it compiled, then you can upload the sketch with the upload subcommand given the board's FQBN and port.

$ arduino-cli upload --port /dev/ttyUSB0 --fqbn esp8266:esp8266:nodemcuv2 blink
esptool.py v2.8
Serial port /dev/ttyUSB0
Connecting....
Chip is ESP8266EX
Features: WiFi
Crystal is 26MHz
MAC: f4:cf:a2:f7:5f:1e
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
Auto-detected Flash size: 4MB
Compressed 261472 bytes to 193129...
Wrote 261472 bytes (193129 compressed) at 0x00000000 in 17.0 seconds (effective 122.9 kbit/s)...
Hash of data verified.

Leaving...
Hard resetting via RTS pin...

DONE.