35 lines
1015 B
Bash
Executable File
35 lines
1015 B
Bash
Executable File
#!/bin/bash
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#dim: control display brightness from terminal
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#usage: dim x
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#where x is an integer for a new display brightness within the [min,max] range of [0,100]
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#user should be part of the video user group to run this wcd ithout sudo
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#James B. Ackman 2019-02-06T15:55:20-08:00
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#check kernel backlight driver names on your machine: `ls -l /sys/class/backlight/*`
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#then set following var, e.g. acpi_video0 nv_backlight or intel_backlight
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backlightDriver="intel_backlight"
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set -e #exit if an error
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percentValue=$1
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if [[ $percentValue -lt "0" || $percentValue -gt "100" ]]; then
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echo 'value should be in range [0,100]'
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exit 1
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fi
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maxBrightness=$(cat /sys/class/backlight/$backlightDriver/max_brightness)
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if [[ $maxBrightness -lt "100" ]]; then
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echo 'max_brightness below 100. Edit this script.'
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exit 1
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fi
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newValue=`echo $(( $maxBrightness / 100 * $percentValue ))`
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if [[ $newValue -le "0" ]]; then
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echo 'value too low'
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exit 1
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fi
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tee /sys/class/backlight/$backlightDriver/brightness <<< $newValue
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