laptop-brightness

#!/bin/bash
# This is an early version of the script, it is not used in material-awesome yet!
# NOTE: This script is intended for hardware not supported properly by "light" on laptops
# PS: THIS IS ONLY INTENDED FOR USE WITH LAPTOP SCREENS!
SCREEN="LVDS|eDP"
# This is for testing only #
#SCREEN="DVI-D-1"
############################

GET_SCREEN=$(xrandr | grep -P "($SCREEN)" | awk '{print $1}')
SET_COMMAND="xrandr --output $GET_SCREEN --brightness"
GET_COMMAND=`xrandr --verbose | grep -iP "(Brightness| connected)" | perl -pe "s/(\t+| connected.+|Brightness)//g" | perl -pe "s/\n/,/" | perl -pe "s/,:/:/g" | perl -pe "s/,/\n/g" | grep $GET_SCREEN | awk '{print $2}'`

# Get the brightness and multiply by 100 to get the percentage then use perl to remove the decimal
BRIGHTNESS=$(echo "$GET_COMMAND*100" | bc | perl -pe "s/\.\d+$//")

helptext () {
    printf "Brightness utility using xrandr as backend.
    This script works when light is not working properly.
    
    SET BRIGHTNESS FOR LVDS (Low-Voltage Differential Signaling, or laptop screen) or eDP Displays
    USAGE set: laptop-brightness set percentage

    GET BRIGHTNESS FOR LVDS or eDP DISPLAYS
    USAGE get: laptop-brightness get
    
    Example set brightness to 57%:
        laptop-brightness set 57

    INCREASE/DECREASE BRIGHTNESS
    USAGE: laptop-brightness add|sub int

    Example increase brightness by 10%: 
        laptop-brightness add 10

    Example decrease brightness by 10%: 
        laptop-brightness sub 10
    
    NOTES: 
    * lowest percentage = 10
"
}

if [ $# == 0 ]; then
    helptext
else
    if [ "$1" == "set" ]
    then
        # Set the brightness and make sure we do not go below 10% or above 100%
        if [ $(($2)) -gt 99 ]
        then
            $SET_COMMAND 1.0
        elif [ $(($2)) -lt 10 ]
        then
            $SET_COMMAND 0.10
        else
            $SET_COMMAND 0.$2
        fi
    elif [ "$1" == "get" ]
    then
        # Print brightness
        echo $BRIGHTNESS
    elif [ "$1" == "add" ]
    then
        # Increment current brightness
        NEW_BRIGHTNESS=$(expr $BRIGHTNESS + $2)

        # Set the brightness and make sure we do not go below 10% or above 100%
        if [ $(($NEW_BRIGHTNESS)) -gt 99 ]; then
            $SET_COMMAND 1.0
        elif [ $(($NEW_BRIGHTNESS)) -lt 10 ]; then
            $SET_COMMAND 0.10
        else
            $SET_COMMAND 0.$NEW_BRIGHTNESS
        fi
    elif [ "$1" == "sub" ]
    then
        # Decrease current brightness
        NEW_BRIGHTNESS=$(expr $BRIGHTNESS - $2)

        # Set the brightness and make sure we do not go below 10% or above 100%
        if [ $(($NEW_BRIGHTNESS)) -gt 99 ]; then
            $SET_COMMAND 1.0
        elif [ $(($NEW_BRIGHTNESS)) -lt 10 ]; then
            $SET_COMMAND 0.10
        else
            $SET_COMMAND 0.$NEW_BRIGHTNESS
        fi      
    else
        helptext
    fi
fi