ddcctlkey.sh

#!/bin/bash

# AMOUNT_OF_DISPLAYS=`ddcctl -h 2>&1 | perl -ne 'print "$1\n" if m/found (\d+) displays/;'`
CURRENT_BR_FILE=/tmp/.last.brightness
MAX_BR=100
MIN_BR=0
if [ -f "$CURRENT_BR_FILE" ]
	then
CURRENT_BR=`cat $CURRENT_BR_FILE`
else
CURRENT_BR="35"	
fi
BR_INCREMENT=5

case "$1" in
    "up" ) 
		CURRENT_BR=$(($CURRENT_BR+$BR_INCREMENT))
		;;
    "down" ) 
		CURRENT_BR=$(($CURRENT_BR-$BR_INCREMENT))
		;;
    *) echo >&2 "Invalid option: $1"; exit 1;;
esac

if [ "$CURRENT_BR" -gt "$MAX_BR" ]
	then
CURRENT_BR=$MAX_BR
fi

if [ "$CURRENT_BR" -lt "$MIN_BR" ]
	then
CURRENT_BR=$MIN_BR
fi

echo "New brightness is $CURRENT_BR"
echo "$CURRENT_BR" > $CURRENT_BR_FILE

/usr/local/bin/ddcctl -d 1 -b $CURRENT_BR