Get Julian date from date string

Hi,
im new for UNIX. i have a problem in date function. please help me to find a solution.

batchdate="29/10/2010"
nextdate="01/11/2010"

i want compare this two date. if my batch date greater than nextdate should prompt error message. how can i do that? as i know its better and safer if i convert this dates to julian format before compare.please advice.

Please review the guidelines for posting homework and repost.

What Operating System and Shell are you running?
(It really matters for "date" questions).