brightness.sh (793B)
1 #!/usr/bin/env bash
2
3 DEV="/sys/class/backlight/intel_backlight"
4 MAX=$(cat "${DEV}/max_brightness")
5 CUR=$(cat "${DEV}/brightness")
6 PER=$((($CUR * 100) / $MAX))
7
8 # If no argument is given, return current value
9 if [[ -z $1 ]]; then
10 echo "$PER"
11 exit 0
12 fi
13
14 # increasing brightness
15 if [[ "$1" == "inc" ]]; then
16
17 # calculate new value in percent, cap at 100%
18 PER_NEW=$((${PER} + ${2}))
19 if [[ $PER_NEW -gt 100 ]]; then
20 PER_NEW=100
21 fi
22
23 fi
24
25 # decrease brightness
26 if [[ "$1" == "dec" ]]; then
27
28 # calculate new value in percent, capt at 5%
29 PER_NEW=$((${PER} - ${2}))
30 if [[ $PER_NEW -lt 5 ]]; then
31 PER_NEW=5
32 fi
33
34 fi
35
36 # calculate numerical value
37 CUR_NEW=$(((${MAX} * ${PER_NEW}) / 100))
38
39 # set new value
40 echo "Setting brightness to $CUR_NEW"
41 echo "$CUR_NEW" > "${DEV}/brightness"
