One other thing, if you're going to go that route, would be to consider consolidating all the exclude strings into one pattern. Something like this. 
if (@strings){
  $re = join "|", map {quotemeta} @strings;
} else {
  $re = undef;
}

foreach my $line (@file1only) {
    print unless defined($re) && /$re/;
}

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In reply to Re: Re: Help with null string behavior in regex? by Eimi Metamorphoumai
in thread Help with null string behavior in regex? by McMahon

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