apod.sh

#!/bin/bash
set -e

wget -O /tmp/apod.txt  http://www.nasa.gov/rss/dyn/lg_image_of_the_day.rss 
urls=$(grep -o '<enclosure [^>]*>' /tmp/apod.txt | grep -o 'http[.]*://[^\"]*')

for url in $urls
do
  if [ ! -z "$url" ]
  then
    echo "Downloading $url"
    wget -N $url
  fi
done