#!/usr/bin/perl -w

##</code><code>##

use warnings;

##</code><code>##

$str = s/.*\-D*?//;

##</code><code>##

$_ = "text1 text2 -f -DFLAG1 -global -DFLAG2 -DFLAG1";
s/.*?(?=-D)//;
print "$_\n";

##</code><code>##

s/[^-]+-[^-]+//;

##</code><code>##

s/
  [^-]+  # Negated character class - match one or more
         # of anything that is not a dash: "text1 text2 "
  -      # match the dash: "-"
  [^-]+  # Negated character class - match one or more
         # of anything that is not a dash: "f "
//x;