distribution/packages/jelos/sources/scripts/batocera-brightness
2022-02-05 09:23:32 -05:00

52 lines
1.1 KiB
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Executable file

#!/bin/bash
if test ! -e /sys/class/backlight/backlight/brightness
then
echo "no brightness found" >&2
exit 1
fi
setValue() {
NEWVAL=$1
XMAX=$2
test "${NEWVAL}" -lt 0 && NEWVAL=0
test "${NEWVAL}" -gt "${XMAX}" && NEWVAL="${XMAX}"
echo "${NEWVAL}" > /sys/class/backlight/backlight/brightness
}
# get
if test $# = 0
then
X=$(cat /sys/class/backlight/backlight/brightness)
XMAX=$(cat /sys/class/backlight/backlight/max_brightness)
echo $(expr "${X}" "*" "100" / "${XMAX}")
exit 0
fi
# set
if test $# = 1
then
XMAX=$(cat /sys/class/backlight/backlight/max_brightness)
NEWVAL=$(expr "${1}" "*" "${XMAX}" / 100)
setValue "${NEWVAL}" "${XMAX}"
exit 0
fi
# set +
if test $# = 2
then
X=$(cat /sys/class/backlight/backlight/brightness)
XMAX=$(cat /sys/class/backlight/backlight/max_brightness)
DELTA=$(expr "${2}" '*' ${XMAX} / 100)
NEWVAL=$(expr "${X}" "${1}" "${DELTA}")
setValue "${NEWVAL}" "${XMAX}"
exit 0
fi
# help
echo "${0}" >&2
echo "${0} + 10" >&2
echo "${0} - 20" >&2
exit 1