awesome-background-changer

#!/bin/bash

WALLPAPER_DIR=$HOME/Pictures/wallpapers
SCRIPT_NAME=$(basename $0)


setWallpaper() {
	local image=$1
	gconftool-2 --type string --set /desktop/gnome/background/picture_filename "$image"
	gconftool-2 --type string --set /desktop/gnome/background/picture_options zoom
	gconftool-2 --type bool --set /desktop/gnome/background/draw_background true
}


# set wallpaper and exit if filenamae supplied
if [[ "$1" ]]; then
	if [[ -f "$1" ]]; then
		cd $(dirname $1)
		image=$PWD/$(basename $1)

	elif [[ -f "$WALLPAPER_DIR/$1" ]]; then
		image=$WALLPAPER_DIR/$1

	else
		printf "File not found: %s\n" "$1"
		exit 1
	fi

	printf "Setting wallpaper to %s\n" "$image"
	setWallpaper "$image"
	exit 0
fi


# Ensure only THIS instance of the script is running
for pid in $(pidof -xo $$ $SCRIPT_NAME 2>/dev/null); do
	other_pids+=" $(pstree -Apl $pid | sed -r 's/[^)]*\(//g; s/\)/ /g' | xargs echo)"
done
[[ $other_pids ]] && kill $other_pids 2>/dev/null


cd $WALLPAPER_DIR
# Main loop
while sleep ${delay:-0}; do
	wallpapers=( * )
	while [[ $choice == $last ]]; do
		index=$(( RANDOM % ${#wallpapers[@]} ))
		choice=${wallpapers[$index]}
	done
	last=$choice
	setWallpaper "$WALLPAPER_DIR/$choice"
	delay=$(( 3600 - $(date '+60*%M+%S' | bc) ))
done