#!/usr/bin/perl

use strict;
use warnings;

my $x = 9*4;
my $name_der_Datei = '/pfad/zur/datei.txt';

# filehandle oeffnen
open(my $fh,">",$name_der_Datei) or die $!;
# in das filehandle schreiben
print $fh $x;
# filehandle schliessen
close $fh