#!/bin/sh
# $Id: osx-set-login-background,v 1.1 2008/12/04 01:20:36 friedman Exp $

# The default system image is used if no arg is specified.
# This is probably just equivalent to deleting the key.

domain=/Library/Preferences/com.apple.loginwindow
key='DesktopPicture'
val=${1-/System/Library/CoreServices/DefaultDesktop.jpg}

defaults write "$domain" "$key" -string "$val" \
  && plutil -convert xml1 "$domain".plist

# eof