blink

#!/bin/bash
# Nick Sweeting 2017
# MIT License

if [[ "$1" == "-h" || "$1" == "--help" || "$1" == "help" ]]; then
    echo "Flash the keyboard [1] times with a [0.15]s delay, between [0] and [1] brightness levels"
    echo "Usage:"
    echo "    blink [times] [duration] [low_brightness] [high_brightness]"
    exit 0
fi

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"  # get the full path to the directory ./blink is in
kbrightness="$DIR/kbrightness"                           # full path to the kbrightness binary

flashes=${1:-'1'}         # how many flashes
duration=${2:-'0.15'}     # duration of each flash in seconds
low_level=${3:-'0'}       # lowest brightness level, 0.0 -> 1.0
high_level=${4:-'1'}      # highest brightness level, 0.0 -> 1.0
before=$("$kbrightness")  # get the current brightness level

for i in $(seq 1 $flashes); do
    "$kbrightness" $low_level
    sleep $duration
    "$kbrightness" $high_level
    sleep $duration
done

# set keyboard back to existing brightness level before blink ran
"$kbrightness" $before