#!/usr/bin/perl
use strict;
use warnings;
use FindBin qw($Bin);

my $filename='./test.txt';

my $real_filename="$Bin/$filename";
open(my $fh, '<', $real_filename) || die("ERROR open $real_filename ($!)\n");
while(my $line=<$fh>)
{
  print $line;
}
close($fh);