#!/usr/bin/env perl

use strict;
use warnings;
use autodie;

my $log_search_re;

{
    open my $keys_fh, '<', 'keys_to_find.txt';
    $log_search_re = qr/(?x: (?<!\w) (?:
        @{[ join '|', map { chomp; "\Q$_" } <$keys_fh> ]}
    ) (?!\w) )/;
}

{
    open my $log_fh, '<', 'log_to_read.txt';
    open my $out_fh, '>', 'log_lines_matched.txt';
    /$log_search_re/ && print $out_fh $_ while <$log_fh>;
}