Cool widget, thanks.
Here's couple of one-liners I use in it:

Root filesystem usage
df /|tail -1|tr -s " "|cut -d " " -f 5

IP address
/sbin/ifconfig `/sbin/route |grep def|tr -s " "|cut -d " " -f 8`|grep inet|sed 's/.*addr:\([^ ]*\).*/\1/'