VAR=/path/to/
AMB=cer
DIRSKE=${VAR}${AMB}
SCRIPT=${DIRSKE}/script.sh
##</code><code>##

#!/usr/bin/perl

use strict;
use warnings;

use AppConfig qw(:expand);
my $config = AppConfig->new({
         CASE => 1,
         GLOBAL => {EXPAND => EXPAND_ALL}
         });

$config->define("VAR=s");
$config->define("AMB=s");
$config->define("DIRSKE=s"); # Maybe this is wrong, but what else?
$config->define("SCRIPT=s");

#read configuration file
$config->file("./file.conf");

#some print
print "Valore VAR -> ".$config->VAR()."\n";
print "Valore AMB -> ".$config->AMB()."\n";
print "Valore DIRSKE -> ".$config->DIRSKE()."\n";
print "Valore SCRIPT -> ".$config->SCRIPT()."\n";

##</code><code>##

Valore VAR -> /path/to/
Valore AMB -> cer
Valore DIRSKE -> 
Valore SCRIPT -> /script.sh

##</code><code>##

Valore VAR -> /path/to/
Valore AMB -> cer
Valore DIRSKE -> /path/to/cer
Valore SCRIPT -> /path/to/cer/script.sh