I'd like to know how you've determined /Host System (?!#)/ doesn't work. It should work fine. 
while (<FH>) {
  print if /^Host System (?!#)/;
  # or perhaps for more whitespace safety
  # print if /^Host\s+System\s+(?![#\s])/
}

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Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart

In reply to Re: Pattern problem by japhy
in thread Pattern problem by Anonymous Monk

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