dims on over a specified period of time

fakesunrise.sh

#!/bin/bash

###################################################
PATH_WHERE_YOUR_SCRIPTS_LIVE=""
export PATH=$PATH:$PATH_WHERE_YOUR_SCRIPTS_LIVE
###################################################

function usage
{
    echo "\nDims a lightbulb over a specified number of minutes"
    echo "\nUsage:\n\t$0 [minutes] \n" 
}

function validate
{
    if [  $# -eq 0 ]; then 
        usage
        exit 1
    fi 

    re='^[0-9]+$'
    if ! [[ $1 =~ $re ]] ; then
       echo "Error: $0 - Not an integer" >&2;
       usage
       exit 1
    fi
}

# set to lowest brightness and turn on
function initialize
{
    sh dim.sh 1
    sh toggle.sh 1
}

function dim_and_sleep
{
    sh dim.sh $1
    sleep $2
}

function timed_dim
{
    seconds=$[$1*60]

    if [ $seconds -lt 100 ]; then
        # calculate each brightness level, update every second 
        for i in $(seq 1 $seconds); do
            dim_and_sleep $(bc <<< "(100 * $i) / $seconds") 1
        done
    else
        # calculate time between increments.
        # brightness level increases by one with each increment
        for i in {1..100}; do
            dim_and_sleep $i $[$seconds/100]
        done
    fi

    # rounding errors may not leave it at full brightness
    sh dim.sh 100
}

validate $@
initialize
timed_dim $1