use warnings;
use subs 'die'; 

#our own print, but it doesn't override the built-in
sub print {
CORE::print scalar(localtime),": "; 
CORE::print(@_);
}

#our own die, will override the built-in
sub die { print "goodbye cruel world\n";}

#calls our custom print
#notice you have to use &print() notation
&print( "hello world\n");

#calls built in print
print "goodbye\n";

#calls our overriden die
die "hello";
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This outputs:

Mon May 28 10:41:21 2001: hello world
goodbye
goodbye cruel world
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You could also use CORE::GLOBAL to override the built-in everywhere (for example if you wanted to add your own custom die handler to catch die in other modules). Here's a package that exports it's own die sub that will be used everywhere -- use with caution!

#mydie.pm
#a package to export a global die, overriding the perl builtin
#reference perldoc perlsub
package mydie;
require Exporter;
use vars qw/@ISA @EXPORT/;
  
@ISA = 'Exporter';
@EXPORT_OK = qw/die/;
      
sub import {
    my $pkg = shift;
    return unless @_;
    my $sym = shift;
    my $where = ($sym =~ s/^GLOBAL_// ? 'CORE::GLOBAL' : caller(0));
    $pkg->export($where, $sym, @_);
    Exporter::import($pkg,@_);
}
                  
sub die {
    print "goodbye cruel world\n";
    CORE::die $_[0];
}
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and here's an example that uses the globally overriden die:

#!/usr/local/bin/perl
use warnings;
use strict;
use mydie qw(die);

print "hello world\n";
#calls the die exported by mydie.pm
die "argh!!!";
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prints:

hello world
goodbye cruel world
argh!!! at mydie.pm line 20.
[download]