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

my %hash_name = (
  "one" => 1,
  "two" => 2,
  "three" => 3,
  "four" => 4
);

open MYFILE, ('/me/out.txt');
foreach my $line (<MYFILE>){
  next if grep {$_ !~ keys %hash_name} $line;
  # above line seems to work but how do I find the hash key that matched?
  #  OR is there a better way to do this altogether?
}
close(MYFILE);