use strict;
use warnings;
use Data::Dumper;
use Config::General;

my $c = Config::General->new(
  -ConfigFile      => \*DATA,
  -InterPolateVars => 1,
);

print Dumper {$c->getall()};

__DATA__
V1=/home/user
V2=$V1/test
V3=$V2/file.txt

##</code><code>##

$VAR1 = {
          'V1' => '/home/user',
          'V2' => '/home/user/test',
          'V3' => '/home/user/test/file.txt'
        };