Install arduino-cli

curl -fsSL https://raw.githubusercontent.com/arduino/arduino-cli/master/install.sh | sh

This whill download the arduino-cli executable in a bin folder inside the current directory. Copy this executable in a location in your PATH to have it available from any position.

You can also setup the bash completion for it with

arduino-cli completion bash > arduino-cli.sh
sudo mv arduino-cli.sh /etc/bash_completion.d/

For other shells refer to https://arduino.github.io/arduino-cli/0.16/command-line-completion/

Initialize the cli

arduino-cli config init
arduino-cli core install arduino:avr
arduino-cli core update-index

Create a new sketch

arduino-cli sketch new ledCube

From now on any arduino-cli command working with the sketch will have to use the name ledCube.

Compile and upload

Use the script flash.sh

Serial monitor

You can use screen to connect to the serial monitor.

IMPORTANT: as long as screen is keeping the connection to the serial device opened you won't be able to flash anything on the Arduino.
You'll have to close screen in order to upload a new sketch.

Open serial monitor

screen /dev/ttyUSB0 115200

Close serial monitor

To close the screen session use the key combination Ctrl-a followed by \\, then confirm on the prompt with y.