#!/usr/bin/perl -w
use strict;

$href->{KEY1}={KEY11=>"a",KEY12=>"b"};
print 'Initial condition for $href->{KEY1}={KEY11=>"a",KEY12=>"b"}'."\n";
print Dumper $href;

${$href->{KEY1}}{KEY11}="c";
print 'Change one key in the hash:${$href->{KEY1}}{KEY11}="c"'."\n";
print Dumper $href;

@{$href->{KEY1}}{[qw/KEY11 KEY12/]}=("c" ,"d");
print 'Change all keys in the slice:@{$href->{KEY1}}{[qw/KEY11 KEY12/]}=("c" ,"d")?'."\n";
print Dumper $href;