How to search a date format from a file an replace with a string in PERL

I am very new to Perl. I am struggling so hard to search a date (such as 10/09/2009, 10-09-2009) from a text file and replace with a string (say DATE) using Perl. Please help me out. Thanks in advance.

Regds

Doren

provide your sample input and show expected output. help us to help you better.

A sample text is "I visited New York on 10-09-2008". The expected output is "I visited New York on DATE". Similary, for another sentence "I visited New York on 10/09/2008". The expected output is "I visited New York on DATE". Also, please help me on how to use regular expression in Perl for such kind of date formats. Thanks in advance.

perldoc perlretut

Thanks a lot. It worked.