nix/home/program/bash/module/Battery.nix

{ ... }:
{
  text = ''
    # Print current battery charge level in percents.
    function battery_level() {
      head -c -1 /sys/class/power_supply/BAT*/capacity
      echo '%'
    }

    # Get battery's info.
    function battery_info() {
      local IFS=$'\n'
      local battery=("$(upower --enumerate | grep battery_BAT)")
      upower -i "''${battery[0]}"
    }
  '';
}