if ( $contents =~ /line3/g ) {
  if ( $contents =~ /(line2-)(\w*)/g ) {
    print $2;
  }
}

##</code><code>##

if ( $contents =~ /^line3/mo ) {
  if ( $contents =~ /^line2-(\w*)/mo ) {
    print $1; # has to be changed as well
  }
}

##</code><code>##

my $string = "abcde abcde adcde";
while ($string =~ /cd/og) {
  print "pos = ", pos $string, "\n";
    if ($string =~ /a(.)/ocg) {
      print "a$1 matched at ",pos $string, "\n";
    }
}