$string = '"I have a 15" latter and a 6" foot arm."';
$string=~s#(^")(.+?)("$)#$1.Quot($2).$3#eg;
##</code><code>##

$string=~s#(^")([^\n]+)("$)#$1.Quot($2).$3#eg;

sub Quot
{
	my ($line)=@_;
	$line=~s#"#&quot;#g;
	return $line;
}