bash date math

[rick henderson <rick henderson wsdtx org>]

Dear list,

In a bash script, I need to know the previous day.

if 03012003 then 02282003
if 05012003 then 04302003
if 08012003 then 07312003

using date, I can get todays date.  But I need date math.

any suggestions on how to do this?

Rick