HN backlight code

backlight.py

#!/usr/bin/python3

import sys

with open('/sys/class/backlight/intel_backlight/max_brightness') as max_brightness_file:
    max_brightness = int(max_brightness_file.readline())
with open('/sys/class/backlight/intel_backlight/brightness', 'r') as brightness_file:
    brightness = int(brightness_file.readline())

default_increment = max_brightness / 50

with open('/sys/class/backlight/intel_backlight/brightness', 'w') as brightness_file:
    if len(sys.argv) == 1:
        print('{} / {}: {:%}'.format(brightness, max_brightness, brightness / max_brightness))
    elif len(sys.argv) == 2:
        arg = sys.argv[1]
        if arg == '+':
            if brightness <= 30:
                brightness += 1
            else:
                brightness += default_increment
        elif arg == '-':
            if brightness <= 30:
                brightness -= 1
            else:
                brightness -= default_increment
        elif arg.isdigit():
            brightness = int(arg)
        brightness = round(brightness)
        brightness = max(1, brightness)
        brightness = min(max_brightness, brightness)
        brightness_file.write(str(brightness))

bl.py

#!/usr/bin/python

from sys import argv

if len(argv) != 2:
    exit(1)

arg = argv[1]
brightness = 0
max_brightness = 0
with open('/sys/class/backlight/intel_backlight/brightness') as f:
    brightness = int(f.read().strip())
with open('/sys/class/backlight/intel_backlight/max_brightness') as f:
    max_brightness = int(f.read().strip())

def clamp(x):
    if x < 1:
        return 1
    if x > max_brightness:
        return max_brightness
    return x

if arg == "+":
    if brightness < 40:
        brightness += 1
    else:
        brightness += 10
elif arg == "-":
    if brightness < 40:
        brightness -= 1
    else:
        brightness -= 10
else:
    brightness = int(arg)

brightness = clamp(brightness)

with open('/sys/class/backlight/intel_backlight/brightness', 'w') as f:
    f.write(str(brightness))

main.rs

use std::env;
use std::fs::{File, OpenOptions};
use std::io::{Read, Write, Seek, SeekFrom};
use std::cmp::{min, max};

fn main() -> Result<(), Box<std::error::Error>> {
    if let Some(command) = env::args().nth(1) {
        let max_brightness = {
            let mut file = File::open("/sys/class/backlight/intel_backlight/max_brightness")?;
            let mut string = String::new();
            file.read_to_string(&mut string)?;
            string.trim().parse::<i32>()?
        };
        let mut brightness_file = OpenOptions::new()
            .read(true)
            .write(true)
            .open("/sys/class/backlight/intel_backlight/brightness")?;
        let mut brightness = {
            let mut string = String::new();
            brightness_file.read_to_string(&mut string)?;
            brightness_file.seek(SeekFrom::Start(0))?;
            string.trim().parse::<i32>()?
        };
        match &*command {
            "+" => {
                if brightness < 40 {
                    brightness += 1;
                } else {
                    brightness += 10;
                }
            }
            "-" => {
                if brightness < 40 {
                    brightness -= 1;
                } else {
                    brightness -= 10;
                }
            }
            _ => {
                brightness = command.trim().parse::<i32>()?;
            }
        }
        brightness = max(1, brightness);
        brightness = min(max_brightness, brightness);
        write!(brightness_file, "{}", brightness);
    } else {
        std::process::exit(1);
    }
    Ok(())
}