Current Perl documentation can be found at perldoc.perl.org.

Here is our local, out-dated (pre-5.6) version:

Why do you want to do thatNULL :-)

If you want to override a predefined function, such as open(), then you'll have to import the new definition from a different module. See Overriding Builtin Functions. There's also an example in Class/Template.

If you want to overload a Perl operator, such as + or **, then you'll want to use the use overload pragma, documented in the overload manpage.

If you're talking about obscuring method calls in parent classes, see Overridden Methods.