Google Now wallpaper changer

update.sh

#! /usr/bin/env sh

# Execute this file:
# - when logging in
# - from a cron job whet the day of time changes (see below)

# An improved version could probably get the location from
# the internet, and use that to figure out sunrise/sunset times.

# Select a random directory.
# Download Google Now wallpapers from:
# - http://brebenel-silviu.deviantart.com/art/Google-Now-353644327
# - http://brebenel-silviu.deviantart.com/art/Google-Now-354098040
# - http://brebenel-silviu.deviantart.com/art/Google-Now-364628160
# - http://brebenel-silviu.deviantart.com/art/Google-Now-377029271
# To keep using only one pack, download just that pack.
DIRS=("$PWD/Google Now "*)
GDIR="${DIRS[RANDOM % ${#DIRS[@]}]}"

# Figure out which to use based on the time of day.
# Change values 4, 7, 19 and 22 to match your local sunrise/sunset times.
hours=$(date +%H)

ok=$((hours<4))
if [ $ok -eq 1 ]
then
	feh --bg-scale "$GDIR/4.jpg"  # night
	exit
fi

ok=$((hours<7))
if [ $ok -eq 1 ]
then
	feh --bg-scale "$GDIR/1.jpg"  # morning
	exit
fi

ok=$((hours<19))
if [ $ok -eq 1 ]
then
	feh --bg-scale "$GDIR/2.jpg"  # daytime
	exit
fi

ok=$((hours<22))
if [ $ok -eq 1 ]
then
	feh --bg-scale "$GDIR/3.jpg"  # evening
	exit
fi

feh --bg-scale "$GDIR/4.jpg"  # night