use strict;
use warnings;

my $h;
{
    my %h;                     # watch from here ...
    $h{fname} = "Foo";
    $holder = \%h;    
}

$holder->{lname} = 'Bar';       

$holder->{email} = 'foo@bar.com';   # ... to before here

##</code><code>##

push @DB::typeahead, (split /\n/, <<EOS);
# Load Carnivore
use Devel::Carnivore
# Line to start watching on
c 7
watch(\\%h) 
# run to point where we want to switch off
c 13
# do so
unwatch \$h
# run to end of program
c
# quit debugger
q
EOS

##</code><code>##

01:26 PM $ perl5.8.5 -d z.pl

Loading DB routines from perl5db.pl version 1.27
Editor support available.

Enter h or `h h' for help, or `man perldebug' for more help.

main::(z.pl:4):	my $h;
main::(z.pl:5):	{
auto(-12)  DB<1> use Devel::Carnivore

auto(-11)  DB<2> # Line to start watching on

auto(-10)  DB<3> c 7
main::(z.pl:7):	    $h{fname} = "Foo";
auto(-9)  DB<4> watch(\%h) 
# variable is now under observation

auto(-8)  DB<5> # run to point where we want to switch off

auto(-7)  DB<6> c 13
> "fname" changed from "" to "Foo"  at z.pl line 7
> "lname" changed from "" to "Bar"  at z.pl line 11
main::(z.pl:13):	$h->{email} = 'foo@bar.com';   # ... to before here
auto(-6)  DB<7> # do so

auto(-5)  DB<8> unwatch $h
# mission completed

auto(-4)  DB<9> # run to end of program

auto(-3)  DB<10> c
Debugged program terminated.  Use q to quit or R to restart,
  use O inhibit_exit to avoid stopping after program termination,
  h q, h R or h O to get additional info.  
auto(-2)  DB<10> # quit debugger

auto(-1)  DB<11> q
01:26 PM $