You can get the memory location of a variable by doing something like this:

use strict;
use warnings;

my @var=(1,2,3);
my $var_ref=\@var;
print "$var_ref\n";
print 0+$var_ref . "\n";
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This would give you output looking something like this:

ARRAY(0x182f26c)
25358956
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I don't know of any way to write directly to a memory location. In fact, AFAIK, the actual hardware protects against such actions by generating (I think) a segmentation fault. I think you'd have to get down to the bare metal to do this. I agree, it's fun to trash your system, but they keep making it harder. Unless, of course, you use Windows.