foreach is a statement, not an expression. It cannot be used as an operand of && or any other operator. Try this instead: 
if (defined $debug) {
  foreach my $key (sort keys %option) {
    print __LINE__ . ": $key = $option{$key}\n"
      if defined($option{$key});
  }
}

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In reply to Re: why doesn't this foreach loop work? by chipmunk
in thread why doesn't this foreach loop work? by blueflashlight

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