# wrong
while (my $line = $fh){

# right
while (my $line = <$fh >){

##</code><code>##

open (my $fh, "<", "test.txt");
my @file_array = (<$fh>);
print @file_array,"\n";

##</code><code>##

#!/usr/bin/perl
use warnings;
use strict;

# use ARGV's magic
@ARGV = "test.txt";

my @results;

while ( <ARGV> ){
   chomp $_;
    if ($_ =~ m/head/){
        push (@results, $_);
      }
}

print "@results\n";