random-wallpaper.sh

#!/bin/bash
## A little script that does REAL random wallpaper changing. Because the OSX's one sucks.

force=false;

while getopts ":f" opt; do
  case $opt in
    f)
      force=true;
      ;;
  esac
done

#Is the computer plugged in?
pluggedin=`/usr/sbin/system_profiler SPPowerDataType | grep "Connected:"`

# If the computer isn't plugged, then no random wallpaper because it drains too much battery
if [[ "$pluggedin" == *No* && $force == false ]]
then
  exit
fi

PrimaryMonitor=$1
SecondaryMonitor=$2
wallpaperSource=~/Dropbox/Wallpapers/*/*
wallpaperDestination=~/Pictures/Wallpapers
TIMESTAMP=$(date +%H:%M:%S)



changeWallpaper() {
WALLPATH=`readlink $1`
PROTECTEDMONITOR="$PrimaryMonitor"
MONITORCHANGED="$SecondaryMonitor"
osascript << END
	tell application "Finder"
		set wall to "$WALLPATH"
		tell application "System Events"
			set theDesktops to a reference to every desktop
			repeat with x from 1 to (count theDesktops)
				if name of item x of the theDesktops is "$MONITORCHANGED" then
					set picture of item x of the theDesktops to wall
				end if
			end repeat
		end tell
	end tell
END
}

primaryWallpaper() {
osascript << END
	tell application "Finder"
		tell application "System Events"
			set theDesktops to a reference to every desktop
			repeat with x from 1 to (count theDesktops)
				if name of item x of the theDesktops is "$1" then
					return picture of item x of the theDesktops
				end if
			end repeat
		end tell
	end tell
END
}


priWall=$(primaryWallpaper "$PrimaryMonitor")

files=(${wallpaperDestination}/*)

wallpaperCount=`ls $wallpaperDestination/*.{jpg,png} | wc -l`

# ## Taking a random file from the folder
randomWallpaper="${files[RANDOM % ${#files[@]}]}"

# ## Setting it as the current wallpaper
changeWallpaper $randomWallpaper
echo "$TIMESTAMP wallpaper changed on $PrimaryMonitor to $randomWallpaper"
if [ $wallpaperCount -gt 1 ]
then
	rm $randomWallpaper
	echo "$TIMESTAMP wallpaper file ($randomWallpaper) removed. Now $wallpaperCount wallpaper(s) remaining" 
else
	rm $wallpaperDestination/*.jpg
	rm $wallpaperDestination/*.png
	ln -s $wallpaperSource $wallpaperDestination
	echo "$TIMESTAMP Wallpaper collection rebuilt"
fi