c:\@Work\Perl\monks>perl -wMstrict -le
"my $inputtext = qq{a multi line\nstring and\nanother line\nthing here\n};
 print qq{<<$inputtext>> \n};
 ;;
 my $newText = replaceText($inputtext, qr{ lin .*? ing }xms, 'xx-xx');
 print qq{<<$newText>>};
 ;;
 sub replaceText {
   my ($inputText, $regex, $replacement) = @_;
   $inputText =~ s/$regex/$replacement/g;
   return $inputText;
   }
"
<<a multi line
string and
another line
thing here
>>

<<a multi xx-xx and
another xx-xx here
>>