#!/bin/bash
# script to blink the thinklight
# by Greg Methvin (greg@methvin.net)

if [ -z "$1" ]; then
    echo "Usage: $(basename $0) <times> [<on delay> [<off delay>]]"
    echo "  <times>: times to blink thinklight"
    echo "  <on delay>: seconds to leave on for each blink (default: 0.25)"
    echo "  <off delay>: seconds to turn off between blinks (default: same as on delay)"
    exit 1
fi

LIGHT=/proc/acpi/ibm/light

TIMES="$1"
[ -n "$2" ] && ONDELAY="$2" || ONDELAY=0.25
[ -n "$3" ] && OFFDELAY="$3" || OFFDELAY="$ONDELAY"

for i in $(seq $TIMES); do
    echo on > $LIGHT
    sleep $ONDELAY
    echo off > $LIGHT
    sleep $OFFDELAY
done