If you only want to match a line that contains both --gnu and -D and then further process the matching line, the following may give you some ideas. Only line 4 satisfies both your conditions and is matched.

use strict;
use warnings;

while(<DATA>){
  chomp;
  if ($_ =~ m/--gnu.+-D/g){
    print "Matched: $_\n";
    # Add code for further processing
  }
}

__DATA__
1. xyz --abc
2. xyz --gnu abc
3. abc -Dxyz
4. xyz --gnu abc -Dxyz def

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In reply to Re: Processing .RES file by arun_kom
in thread Processing .RES file by raghvens

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