Hacky hacks to make things work in Linux

brightness.service

# Evan Wilde              <etcwilde@uvic.ca>
# May 19 2016
# /usr/lib/systemd/system/brightness.service
# Grants non-root permissions to the backlight file so that it can be set by a user process
#

[Unit]
Description=Grants non-root write access to the brightness file

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/chmod 666 /sys/class/backlight/intel_backlight/brightness

brightness.sh

#!/bin/sh
# Evan Wilde      <etcwilde@uvic.ca>
# May 2016
# Allows a user to make adjustments to the monitor brightness

brightness_directory="/sys/class/backlight/intel_backlight"
max_brightness=`cat $brightness_directory/max_brightness`
current_brightness=`cat $brightness_directory/brightness`

num_re='^[1-9][0-9]*$'
option="${1}"
case ${option} in
  ++) # Increase Backlight
    number=${2-5}
    if ! [[ $number =~ $num_re ]] ; then
      number=5
    fi
    if [[ $max_brightness -lt $((current_brightness + number)) ]] ; then
      echo $max_brightness > $brightness_directory/brightness
    else
      echo $((current_brightness + number)) > $brightness_directory/brightness
    fi
    ;;
  --) # Decrease backlight
    number=${2-5}
    if ! [[ $number =~ $num_re ]] ; then
      number=5
    fi
    if [[ 0 -gt $((current_brightness - number)) ]] ; then
      echo 0 >> $brightness_directory/brightness
    else
      echo $((current_brightness - number)) > $brightness_directory/brightness
    fi
    ;;
  +) echo $max_brightness > $brightness_directory/brightness ;; # Set to max
  -) echo 0 > $brightness_directory/brightness ;; # Set to min
  =) # Set brightness value
    number=${2-5}
    if ! [[ $number =~ $num_re ]] ; then
      number=$max_brightness
    fi

    if [[ $number -le 0 ]] ; then
      number=0
    elif [[ $number -ge $max_brightness ]] ; then
      number=$max_brightness
    fi
    echo $number > $brightness_directory/brightness
    ;;
  *) echo " `basename ${0}`: usage: [++ [LEVEL] | -- [LEVEL] | + | -  | = [LEVEL]]"
    exit 1 ;;
esac