#!/usr/bin/perl

use strict;
use warnings;

my $string = 'my-test-string';

open(my $fh, '>', \$string) 
or die "Could not open string for writing";
print $fh "my-test-string\n";

open($fh, '<', \$string)
or die "Could not open string for reading";

my $x = <$fh>;
print $x, "\n";