Crawler mínimo para imagens da NASA

apod.sh

#!/bin/bash
#gets apod.nasa.gov html and
wget -qO- apod.nasa.gov | 
#filters to <IMG SRC="image/xxxx/nnnnnnn...jpg" 
grep IMG |
#cuts out whats outside quotes
cut -d '"' -f2 |
#prepends link
awk '{print "http://apod.nasa.gov/apod/" $0}' |
#downloads the resulting url to ~/Pictures
xargs wget --directory-prefix=/home/$USER/Pictures