Xubuntu: Random Wallpaper from a folder (recursive)

ranbg

#!/bin/bash
# script: ranbg
# version 11.04
# description: randomly replace gnome background with one from a directory
# credits: Sudhanshu [http://s7dhansh.wordpress.com]
# license: GPL
# Requires imagemagick for xfce


# === User Options =============================================================
WP_PATH="$HOME/.wallpapers/"
EXTENSIONS="jpg png jpeg JPG PNG"
TMP_DIR="$HOME/.tmp"
TMP_BG_LIST="$TMP_DIR/bg_change_list"
# === End User Options =========================================================

help () {
	cat << EOF
ranbg version 11.04
Set ups random desktop wallpapers
Usage: ranbg [OPTIONS]
       ranbg --rm
       ranbg --help

Options:
--rm                deletes the current wallpaper and uses another
--help              shows help options

Current wallpaper folder for resume files: $WP_PATH
Current tmp folder for resume files: $TMP_DIR

EOF
	exit
}

# Basic random wallpaper generation

generateWallpaper () {
    rm -f $TMP_BG_LIST
    for extension in $EXTENSIONS
    do
	    find $WP_PATH -iregex ".*.$extension" >> "$TMP_BG_LIST"
    done

    cnt=`wc -l "$TMP_BG_LIST" | cut -f1 -d" "`
    all_bgs=`echo \`expr $RANDOM % $cnt\``

    selected_bg=`head -n$all_bgs "$TMP_BG_LIST" | tail -n1`

    echo "$selected_bg"
    echo -e "$selected_bg">$HOME/.tmp/wallpaper
}

exportDbus () {
    # Get the pid of nautilus
    nautilus_pid=$(pgrep -u $LOGNAME -n nautilus)

    # If nautilus isn't running, just exit silently
    if [ -z "$nautilus_pid" ]; then
    exit 0
    fi

    # Grab the DBUS_SESSION_BUS_ADDRESS variable from nautilus's environment
    eval $(tr '\0' '\n' < /proc/$nautilus_pid/environ | grep '^DBUS_SESSION_BUS_ADDRESS=')

    # Check that we actually found it
    if [ -z "$DBUS_SESSION_BUS_ADDRESS" ]; then
    echo "Failed to find bus address" >&2
    exit 1
    fi

    # export it so that child processes will inherit it
    export DBUS_SESSION_BUS_ADDRESS
}

gnome () {
    nautilus=$(gconftool-2 -g /apps/nautilus/preferences/show_desktop)
    
    if [ "$nautilus" == "true" ]; then
      # If nautilus is managing desktop
      exportDbus #For cron
      gconftool-2 -t string -s /desktop/gnome/background/picture_filename "$selected_bg"
    else
      # Else use feh
      export DISPLAY=:0.0 #For cron
      feh --bg-scale "$selected_bg"
    fi
}


xfce () {
    echo -e "# xfce backdrop list\n$selected_bg">$HOME/.config/xfce4/desktop/backdrop.list
    xfdesktop -reload

    rm $TMP_DIR/splash.jpg
    cp "$selected_bg" $TMP_DIR/splash.jpg

    convert $TMP_DIR/splash.jpg -scale X772 $TMP_DIR/splash.jpg
    convert $TMP_DIR/splash.jpg -gravity south -background black -splice 0x24 $TMP_DIR/wallpaper.jpg
}

deleteWallpaper () {
    wp=`cat $HOME/.tmp/wallpaper`
    echo "Deleting: $wp"
    rm -i "$wp"
}

# parse command line
index=0
while [ "$1" != "" ];
do
	if [ "${1:0:1}" = "-" ]; then
		case "$1" in
			--help | -help )
				help
				;;
			--rm )
				deleteWallpaper
				;;
			* )
				echo Unknown option $1
				exit 1
				;;
		esac
	else
		let "index+=1"
		case $index in
			* )
				echo Too many arguments
				help
				;;
		esac
	fi
	shift
done

generateWallpaper

# Check sessions: gnome or xfce
gnome_pid=$(pgrep -u $LOGNAME -n gnome-session)
xfce_pid=$(pgrep -u $LOGNAME -n xfce4-session)

if [ -z "$xfce_pid" ]; then
    if [ -z "$gnome_pid" ]; then
        echo "Neither Gnome nor XFCE"
        exit
    fi

    ##---------------- FOR GNOME --------------
    gnome
    exit 2
    
    ##---------------- END GNOME----------
fi

##----------------- FOR XFCE ---------------
xfce
exit 3
##-------------- END XFCE ------------------